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Vallecillo-Zúniga ML, Rathgeber M, Poulson D, Kartchner B, Luddington J, Gill H, Hayes S, Teynor M, Stowell CS, Arthur CM, Stowell SR, Van Ry PM. Evaluating Therapeutic Activity of Galectin-1 in Sarcolemma Repair of Skeletal Muscle. Methods Mol Biol 2022; 2442:663-683. [PMID: 35320552 DOI: 10.1007/978-1-0716-2055-7_36] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Galectin-1 is a small (14.5 kDa) multifunctional protein with cell-cell and cell-ECM adhesion due to interactions with the carbohydrate recognition domain (CRD). In two types of muscular dystrophies, this lectin protein has shown therapeutic properties, including positive regulation of skeletal muscle differentiation and regeneration. Both Duchenne and limb-girdle muscular dystrophy 2B (LGMD2B) are subtypes of muscular dystrophies characterized by deficient membrane repair, muscle weakness, and eventual loss of ambulation. This chapter explains confocal techniques such as laser injury, calcium imaging, and galectin-1 localization to examine the effects of galectin-1 on membrane repair in injured LGMD2B models.
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Affiliation(s)
| | - Matthew Rathgeber
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA
| | - Daniel Poulson
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA
| | - Braden Kartchner
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA
| | - Jacob Luddington
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA
| | - Hailie Gill
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA
| | - Spencer Hayes
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA
| | - Matthew Teynor
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA
| | - Caleb S Stowell
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA
| | - Connie M Arthur
- Joint Program in Transfusion Medicine, Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
- Harvard Glycomics Center, Harvard Medical School, Boston, MA, USA
| | - Sean R Stowell
- Joint Program in Transfusion Medicine, Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
- Harvard Glycomics Center, Harvard Medical School, Boston, MA, USA
| | - Pam M Van Ry
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA.
- Department of Biochemistry, Brigham Young University, Provo, UT, USA.
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Maltsev AV, Evdokimovskii EV, Kokoz YM. α2-Adrenoceptor signaling in cardiomyocytes of spontaneously hypertensive rats starts to impair already at early age. Biochem Biophys Res Commun 2019; 512:908-913. [PMID: 30929926 DOI: 10.1016/j.bbrc.2019.03.117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Accepted: 03/18/2019] [Indexed: 11/26/2022]
Abstract
α2-Adrenoceptors (α2-AR) found in the cardiomyocyte's sarcolemma represent a very important negative feedback for control of myocardial contractility by endogenous catecholamines. Earlier, we showed that the endogenous neurotransmitter agmatine in micromolar concentrations via α2-AR activates the nitric oxide (NO) synthesis, enhancing the Ca2+ pumping into sarcoplasmic reticulum (SR). In the millimolar doses it inhibits Ca2+ sequestration by SR Ca2+ ATPase (SERCA), acting through the first type of imidazoline receptors. Here, we study the functional activity of agmatine, as well as a specific α2-agonist, guanabenz, in respect to spontaneous Ca2+-transients in SHR cardiomyocytes of the early age (2-2.5 months), and adulthood animals (8-9 months). α2-mediated cardioprotective effect was almost twofold decreased in SHR cardiac cells compared to normotensive rats of the corresponding age, despite the fact that both α2A- and α2B-AR protein levels were significantly increased in SHR cardiomyocytes. NO-mediated facilitation of SERCA activity is substantially reduced in SHR cardiomyocytes vs. normotensive rats. These data suggest that the SHR phenotype starting from early age shows signs of the impaired sarcolemmal α2-AR signaling, which can aggravate the development of this cardiovascular pathology.
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Affiliation(s)
- A V Maltsev
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Moscow Region, Pushchino, Institutskaya, 3, 142290, Russia; Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Butlerova 5А, 117485, Russia.
| | - E V Evdokimovskii
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Moscow Region, Pushchino, Institutskaya, 3, 142290, Russia
| | - Y M Kokoz
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Moscow Region, Pushchino, Institutskaya, 3, 142290, Russia
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Sciuto KJ, Deng SW, Venable PW, Warren M, Warren JS, Zaitsev AV. Cyclosporine-insensitive mode of cell death after prolonged myocardial ischemia: Evidence for sarcolemmal permeabilization as the pivotal step. PLoS One 2018; 13:e0200301. [PMID: 29975744 PMCID: PMC6033462 DOI: 10.1371/journal.pone.0200301] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 06/23/2018] [Indexed: 11/18/2022] Open
Abstract
A prominent theory of cell death in myocardial ischemia/reperfusion (I/R) posits that the primary and pivotal step of irreversible cell injury is the opening of the mitochondrial permeability transition (MPT) pore. However, the predominantly positive evidence of protection against infarct afforded by the MPT inhibitor, Cyclosporine A (CsA), in experimental studies is in stark contrast with the overall lack of benefit found in clinical trials of CsA. One reason for the discrepancy might be the fact that relatively short experimental ischemic episodes (<1 hour) do not represent clinically-realistic durations, usually exceeding one hour. Here we tested the hypothesis that MPT is not the primary event of cell death after prolonged (60–80 min) episodes of global ischemia. We used confocal microcopy in Langendorff-perfused rabbit hearts treated with the electromechanical uncoupler, 2,3-Butanedione monoxime (BDM, 20 mM) to allow tracking of MPT and sarcolemmal permeabilization (SP) in individual ventricular myocytes. The time of the steepest drop in fluorescence of mitochondrial membrane potential (ΔΨm)-sensitive dye, TMRM, was used as the time of MPT (TMPT). The time of 20% uptake of the normally cell-impermeable dye, YO-PRO1, was used as the time of SP (TSP). We found that during reperfusion MPT and SP were tightly coupled, with MPT trending slightly ahead of SP (TSP-TMPT = 0.76±1.31 min; p = 0.07). These coupled MPT/SP events occurred in discrete myocytes without crossing cell boundaries. CsA (0.2 μM) did not reduce the infarct size, but separated SP and MPT events, such that detectable SP was significantly ahead of MPT (TSP -TMPT = -1.75±1.28 min, p = 0.006). Mild permeabilization of cells with digitonin (2.5–20 μM) caused coupled MPT/SP events which occurred in discrete myocytes similar to those observed in Control and CsA groups. In contrast, deliberate induction of MPT by titration with H2O2 (200–800 μM), caused propagating waves of MPT which crossed cell boundaries and were uncoupled from SP. Taken together, these findings suggest that after prolonged episodes of ischemia, SP is the primary step in myocyte death, of which MPT is an immediate and unavoidable consequence.
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Affiliation(s)
- Katie J. Sciuto
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States of America
- Department of Bioengineering, University of Utah, Salt Lake City, Utah, United States of America
| | - Steven W. Deng
- Department of Bioengineering, University of Utah, Salt Lake City, Utah, United States of America
| | - Paul W. Venable
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States of America
- Department of Bioengineering, University of Utah, Salt Lake City, Utah, United States of America
| | - Mark Warren
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States of America
- Department of Bioengineering, University of Utah, Salt Lake City, Utah, United States of America
| | - Junco S. Warren
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States of America
- Department of Internal Medicine, School of Medicine, University of Utah, Salt Lake City, Utah, United States of America
| | - Alexey V. Zaitsev
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, Utah, United States of America
- Department of Bioengineering, University of Utah, Salt Lake City, Utah, United States of America
- * E-mail:
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Quattrocelli M, Barefield DY, Warner JL, Vo AH, Hadhazy M, Earley JU, Demonbreun AR, McNally EM. Intermittent glucocorticoid steroid dosing enhances muscle repair without eliciting muscle atrophy. J Clin Invest 2017; 127:2418-2432. [PMID: 28481224 DOI: 10.1172/jci91445] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 03/09/2017] [Indexed: 12/20/2022] Open
Abstract
Glucocorticoid steroids such as prednisone are prescribed for chronic muscle conditions such as Duchenne muscular dystrophy, where their use is associated with prolonged ambulation. The positive effects of chronic steroid treatment in muscular dystrophy are paradoxical because these steroids are also known to trigger muscle atrophy. Chronic steroid use usually involves once-daily dosing, although weekly dosing in children has been suggested for its reduced side effects on behavior. In this work, we tested steroid dosing in mice and found that a single pulse of glucocorticoid steroids improved sarcolemmal repair through increased expression of annexins A1 and A6, which mediate myofiber repair. This increased expression was dependent on glucocorticoid response elements upstream of annexins and was reinforced by the expression of forkhead box O1 (FOXO1). We compared weekly versus daily steroid treatment in mouse models of acute muscle injury and in muscular dystrophy and determined that both regimens provided comparable benefits in terms of annexin gene expression and muscle repair. However, daily dosing activated atrophic pathways, including F-box protein 32 (Fbxo32), which encodes atrogin-1. Conversely, weekly steroid treatment in mdx mice improved muscle function and histopathology and concomitantly induced the ergogenic transcription factor Krüppel-like factor 15 (Klf15) while decreasing Fbxo32. These findings suggest that intermittent, rather than daily, glucocorticoid steroid regimen promotes sarcolemmal repair and muscle recovery from injury while limiting atrophic remodeling.
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Hissa B, Oakes PW, Pontes B, Ramírez-San Juan G, Gardel ML. Cholesterol depletion impairs contractile machinery in neonatal rat cardiomyocytes. Sci Rep 2017; 7:43764. [PMID: 28256617 PMCID: PMC5335656 DOI: 10.1038/srep43764] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 01/27/2017] [Indexed: 02/06/2023] Open
Abstract
Cholesterol regulates numerous cellular processes. Depleting its synthesis in skeletal myofibers induces vacuolization and contraction impairment. However, little is known about how cholesterol reduction affects cardiomyocyte behavior. Here, we deplete cholesterol by incubating neonatal cardiomyocytes with methyl-beta-cyclodextrin. Traction force microscopy shows that lowering cholesterol increases the rate of cell contraction and generates defects in cell relaxation. Cholesterol depletion also increases membrane tension, Ca2+ spikes frequency and intracellular Ca2+ concentration. These changes can be correlated with modifications in caveolin-3 and L-Type Ca2+ channel distributions across the sarcolemma. Channel regulation is also compromised since cAMP-dependent PKA activity is enhanced, increasing the probability of L-Type Ca2+ channel opening events. Immunofluorescence reveals that cholesterol depletion abrogates sarcomeric organization, changing spacing and alignment of α-actinin bands due to increase in proteolytic activity of calpain. We propose a mechanism in which cholesterol depletion triggers a signaling cascade, culminating with contraction impairment and myofibril disruption in cardiomyocytes.
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Affiliation(s)
- Barbara Hissa
- James Franck Institute, Institute for Biophysical Dynamics and Physics Department, University of Chicago, Chicago, IL, United States
| | - Patrick W. Oakes
- James Franck Institute, Institute for Biophysical Dynamics and Physics Department, University of Chicago, Chicago, IL, United States
| | - Bruno Pontes
- LPO-COPEA, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Guillermina Ramírez-San Juan
- James Franck Institute, Institute for Biophysical Dynamics and Physics Department, University of Chicago, Chicago, IL, United States
| | - Margaret L. Gardel
- James Franck Institute, Institute for Biophysical Dynamics and Physics Department, University of Chicago, Chicago, IL, United States
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Panasiuk OS, Shysh AM, Moibenko OO. OMEGA-3 POLYUNSATURATED FATTY ACIDS NORMALIZE THE FUNCTION OF MITOCHONDRIA, ACTIVITY OF ENZYMES OF PROOXIDANT-ANTIOXIDANT SYSTEM AND THE EXPRESSION OF CYTOCHROME Р450 2Е1 AFTER ISOPROTERENOLINDUCED MYOCARDIAL INJURY. ACTA ACUST UNITED AC 2016. [PMID: 29537227 DOI: 10.15407/fz62.02.064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We have studied the influence of dietary ω-3 polyunsaturated fatty acids (ω-3 PUFA) on the functioning of subsarcolemmal and interfibrillar mitochondrial fractions of rat myocardium, changes in expression of cytochrome P450 (CYP2E1) and the activity of enzymes of prooxidant-antioxidant system after isoproterenol-induced myocardial injury. It has been found that in vivo administration of ω-3 PUFA (Epadol 0.1 ml/100 gr of weight for 4 weeks) significantly reduced the swelling of subsarcolemmal and interfibrillar mitochondrial fractions by 65.52% 54.84% respectively, pointing for a decrease of damage of the mitochondrial function evoked by in vivo administration of isoproterenol. In vivo administration of ω-3 PUFAs prevents a decrease in the activity of antioxidant enzymes catalase and superoxide dismutase (2.65 and 7.1- fold, respectively) after isoproterenol-induced myocardial injury. We suggest that the development of oxidative stress after isoproterenol-induced myocardial injury can be caused by a significant increase in the expression of cytochrome P450 2E1 (73.3%), and administration of ω-3 PUFAs prevents such changes.
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Squecco R, Garella R, Idrizaj E, Nistri S, Francini F, Baccari MC. Relaxin Affects Smooth Muscle Biophysical Properties and Mechanical Activity of the Female Mouse Colon. Endocrinology 2015; 156:4398-410. [PMID: 26360621 DOI: 10.1210/en.2015-1428] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The hormone relaxin (RLX) has been reported to influence gastrointestinal motility in mice. However, at present, nothing is known about the effects of RLX on the biophysical properties of the gastrointestinal smooth muscle cells (SMCs). Other than extending previous knowledge of RLX on colonic motility, the purpose of this study was to investigate the ability of the hormone to induce changes in resting membrane potential (RMP) and on sarcolemmal ion channels of colonic SMCs of mice that are related to its mechanical activity. To this aim, we used a combined mechanical and electrophysiological approach. In the mechanical experiments, we observed that RLX caused a decay of the basal tone coupled to an increase of the spontaneous contractions, completely abolished by the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]-quinoxalin-1-one (ODQ). The electrophysiological results indicate for the first time that RLX directly affects the SMC biophysical properties inducing hyperpolarization of RMP and cycles of slow hyperpolarization/depolarization oscillations. The effects of RLX on RMP were abolished by ODQ as well as by a specific inhibitor of the cGMP-dependent protein kinase, KT5823. RLX reduced Ca(2+) entry through the voltage-dependent L-type channels and modulated either voltage- or ATP-dependent K(+) channels. These effects were abolished by ODQ, suggesting the involvement of the nitric oxide/guanylate cyclase pathway in the effects of RLX on RMP and ion channel modulation. These actions of RLX on membrane properties may contribute to the regulation of the proximal colon motility by the nitric oxide/cGMP/cGMP-dependent protein kinase pathway.
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MESH Headings
- Animals
- Biophysical Phenomena/drug effects
- Calcium/metabolism
- Calcium Channels, L-Type/drug effects
- Calcium Channels, L-Type/metabolism
- Carbazoles/pharmacology
- Colon/cytology
- Colon/drug effects
- Colon/metabolism
- Cyclic GMP-Dependent Protein Kinases/antagonists & inhibitors
- Female
- Gastrointestinal Motility
- Guanylate Cyclase/antagonists & inhibitors
- KATP Channels/drug effects
- KATP Channels/metabolism
- Membrane Potentials/drug effects
- Mice
- Muscle Contraction/drug effects
- Muscle, Smooth/drug effects
- Myenteric Plexus/metabolism
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Oxadiazoles/pharmacology
- Patch-Clamp Techniques
- Potassium Channels, Voltage-Gated/drug effects
- Potassium Channels, Voltage-Gated/metabolism
- Quinoxalines/pharmacology
- RNA, Messenger/metabolism
- Receptors, G-Protein-Coupled/genetics
- Receptors, G-Protein-Coupled/metabolism
- Relaxin/pharmacology
- Reverse Transcriptase Polymerase Chain Reaction
- Sarcolemma/drug effects
- Sarcolemma/metabolism
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Affiliation(s)
- Roberta Squecco
- Sections of Physiology (R.S., R.G., E.I., F.F., M.C.B.) and Anatomy and Histology (S.N.), Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy
| | - Rachele Garella
- Sections of Physiology (R.S., R.G., E.I., F.F., M.C.B.) and Anatomy and Histology (S.N.), Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy
| | - Eglantina Idrizaj
- Sections of Physiology (R.S., R.G., E.I., F.F., M.C.B.) and Anatomy and Histology (S.N.), Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy
| | - Silvia Nistri
- Sections of Physiology (R.S., R.G., E.I., F.F., M.C.B.) and Anatomy and Histology (S.N.), Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy
| | - Fabio Francini
- Sections of Physiology (R.S., R.G., E.I., F.F., M.C.B.) and Anatomy and Histology (S.N.), Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy
| | - Maria Caterina Baccari
- Sections of Physiology (R.S., R.G., E.I., F.F., M.C.B.) and Anatomy and Histology (S.N.), Department of Experimental and Clinical Medicine, University of Florence, 50134 Florence, Italy
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Romani AMP. Effect of acute and prolonged alcohol administration on Mg(2+) homeostasis in cardiac cells. Alcohol 2015; 49:265-73. [PMID: 25800156 DOI: 10.1016/j.alcohol.2015.02.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 01/27/2015] [Accepted: 02/10/2015] [Indexed: 11/15/2022]
Abstract
Alcoholic cardiomyopathy represents a major clinical complication in chronic alcoholics. Previous studies from our laboratory indicate that acute and chronic exposure of liver cells to ethanol results in a major loss of cellular Mg(2+) as a result of alcohol oxidation. We investigated whether exposure to ethanol induces a similar Mg(2+) loss in cardiac cells. The results indicate that chronic exposure to a 6% ethanol-containing diet depleted cardiac myocytes of >25% of their cellular Mg(2+) content. Acute ethanol exposure, instead, induced a time- and dose-dependent manner of Mg(2+) extrusion from perfused hearts and collagenase-dispersed cardiac ventricular myocytes. Pretreatment with chlormethiazole prevented ethanol-induced Mg(2+) loss to a large extent, suggesting a role of ethanol oxidation via cyP4502E1 in the process. Magnesium extrusion across the sarcolemma occurred via the amiloride-inhibited Na(+)/Mg(2+) exchanger. Taken together, our data indicate that Mg(2+) extrusion also occurs in cardiac cells exposed to ethanol as a result of alcohol metabolism by cyP4502E1. The extrusion, which is mediated by the Na(+)/Mg(2+) exchanger, only occurs at doses of ethanol ≥0.1%, and depends on ethanol-induced decline in cellular ATP. The significance of Mg(2+) extrusion for the onset of alcoholic cardiomyopathy remains to be elucidated.
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Affiliation(s)
- Andrea M P Romani
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA.
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Angin Y, Schwenk RW, Nergiz-Unal R, Hoebers N, Heemskerk JWM, Kuijpers MJ, Coumans WA, van Zandvoort MAMJ, Bonen A, Neumann D, Glatz JFC, Luiken JJFP. Calcium signaling recruits substrate transporters GLUT4 and CD36 to the sarcolemma without increasing cardiac substrate uptake. Am J Physiol Endocrinol Metab 2014; 307:E225-36. [PMID: 24895286 DOI: 10.1152/ajpendo.00655.2013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Activation of AMP-activated protein kinase (AMPK) in cardiomyocytes induces translocation of glucose transporter GLUT4 and long-chain fatty acid (LCFA) transporter CD36 from endosomal stores to the sarcolemma to enhance glucose and LCFA uptake, respectively. Ca(2+)/calmodulin-activated kinase kinase-β (CaMKKβ) has been positioned directly upstream of AMPK. However, it is unknown whether acute increases in [Ca(2+)]i stimulate translocation of GLUT4 and CD36 and uptake of glucose and LCFA or whether Ca(2+) signaling converges with AMPK signaling to exert these actions. Therefore, we studied the interplay between Ca(2+) and AMPK signaling in regulation of cardiomyocyte substrate uptake. Exposure of primary cardiomyocytes to inhibitors or activators of Ca(2+) signaling affected neither AMPK-Thr(172) phosphorylation nor basal and AMPK-mediated glucose and LCFA uptake. Despite their lack of an effect on substrate uptake, Ca(2+) signaling activators induced GLUT4 and CD36 translocation. In contrast, AMPK activators stimulated GLUT4/CD36 translocation as well as glucose/LCFA uptake. When cardiomyocytes were cotreated with Ca(2+) signaling and AMPK activators, Ca(2+) signaling activators further enhanced AMPK-induced glucose/LCFA uptake. In conclusion, Ca(2+) signaling shows no involvement in AMPK-induced GLUT4/CD36 translocation and substrate uptake but elicits transporter translocation via a separate pathway requiring CaMKKβ/CaMKs. Ca(2+)-induced transporter translocation by itself appears to be ineffective to increase substrate uptake but requires additional AMPK activation to effectuate transporter translocation into increased substrate uptake. Ca(2+)-induced transporter translocation might be crucial under excessive cardiac stress conditions that require supraphysiological energy demands. Alternatively, Ca(2+) signaling might prepare the heart for substrate uptake during physiological contraction by inducing transporter translocation.
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Affiliation(s)
| | | | | | | | | | | | | | - Marc A M J van Zandvoort
- Molecular Cell Biology, School for Cardiovascular Diseases, Maastricht University, Maastricht, The Netherlands
| | - Arend Bonen
- Department of Human Health and Nutritional Sciences, University of Guelph, Guelph, Ontario, Canada
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Pierno S, Tricarico D, Liantonio A, Mele A, Digennaro C, Rolland JF, Bianco G, Villanova L, Merendino A, Camerino GM, De Luca A, Desaphy JF, Camerino DC. An olive oil-derived antioxidant mixture ameliorates the age-related decline of skeletal muscle function. Age (Dordr) 2014; 36:73-88. [PMID: 23716142 PMCID: PMC3889891 DOI: 10.1007/s11357-013-9544-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 05/14/2013] [Indexed: 06/02/2023]
Abstract
Age-related skeletal muscle decline is characterized by the modification of sarcolemma ion channels important to sustain fiber excitability and to prevent metabolic dysfunction. Also, calcium homeostasis and contractile function are impaired. In the aim to understand whether these modifications are related to oxidative damage and can be reverted by antioxidant treatment, we examined the effects of in vivo treatment with an waste water polyphenolic mixture (LACHI MIX HT) supplied by LACHIFARMA S.r.l. Italy containing hydroxytirosol (HT), gallic acid, and homovanillic acid on the skeletal muscles of 27-month-old rats. After 6-week treatment, we found an improvement of chloride ClC-1 channel conductance, pivotal for membrane electrical stability, and of ATP-dependent potassium channel activity, important in coupling excitability with fiber metabolism. Both of them were analyzed using electrophysiological techniques. The treatment also restored the resting cytosolic calcium concentration, the sarcoplasmic reticulum calcium release, and the mechanical threshold for contraction, an index of excitation-contraction coupling mechanism. Muscle weight and blood creatine kinase levels were preserved in LACHI MIX HT-treated aged rats. The antioxidant activity of LACHI MIX HT was confirmed by the reduction of malondialdehyde levels in the brain of the LACHI MIX HT-treated aged rats. In comparison, the administration of purified HT was less effective on all the parameters studied. Although muscle function was not completely recovered, the present study provides evidence of the beneficial effects of LACHI MIX HT, a natural compound, to ameliorate skeletal muscle functional decline due to aging-associated oxidative stress.
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Affiliation(s)
- Sabata Pierno
- Section of Pharmacology, Department of Pharmacy & Drug Sciences, University of Bari "Aldo Moro", Via Orabona 4-campus, 70125, Bari, Italy,
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11
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Liantonio A, Gramegna G, Carbonara G, Sblendorio VT, Pierno S, Fraysse B, Giannuzzi V, Rizzi L, Torsello A, Camerino DC. Growth hormone secretagogues exert differential effects on skeletal muscle calcium homeostasis in male rats depending on the peptidyl/nonpeptidyl structure. Endocrinology 2013; 154:3764-75. [PMID: 23836033 DOI: 10.1210/en.2013-1334] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The orexigenic and anabolic effects induced by ghrelin and the synthetic GH secretagogues (GHSs) are thought to positively contribute to therapeutic approaches and the adjunct treatment of a number of diseases associated with muscle wasting such as cachexia and sarcopenia. However, many questions about the potential utility and safety of GHSs in both therapy and skeletal muscle function remain unanswered. By using fura-2 cytofluorimetric technique, we determined the acute effects of ghrelin, as well as of peptidyl and nonpeptidyl synthetic GHSs on calcium homeostasis, a critical biomarker of muscle function, in isolated tendon-to-tendon male rat skeletal muscle fibers. The synthetic nonpeptidyl GHSs, but not peptidyl ghrelin and hexarelin, were able to significantly increase resting cytosolic calcium [Ca²⁺]i. The nonpeptidyl GHS-induced [Ca²⁺]i increase was independent of GHS-receptor 1a but was antagonized by both thapsigargin/caffeine and cyclosporine A, indicating the involvement of the sarcoplasmic reticulum and mitochondria. Evaluation of the effects of a pseudopeptidyl GHS and a nonpeptidyl antagonist of the GHS-receptor 1a together with a drug-modeling study suggest the conclusion that the lipophilic nonpeptidyl structure of the tested compounds is the key chemical feature crucial for the GHS-induced calcium alterations in the skeletal muscle. Thus, synthetic GHSs can have different effects on skeletal muscle fibers depending on their molecular structures. The calcium homeostasis dysregulation specifically induced by the nonpeptidyl GHSs used in this study could potentially counteract the beneficial effects associated with these drugs in the treatment of muscle wasting of cachexia- or other age-related disorders.
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MESH Headings
- Animals
- Appetite Stimulants/adverse effects
- Appetite Stimulants/pharmacology
- Calcium Signaling/drug effects
- Cell Line
- Cell Membrane Permeability/drug effects
- Cell Survival/drug effects
- Cytosol/drug effects
- Cytosol/metabolism
- Ghrelin/analogs & derivatives
- Ghrelin/metabolism
- Growth Hormone/metabolism
- Male
- Mitochondria, Muscle/drug effects
- Mitochondria, Muscle/metabolism
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/metabolism
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Oligopeptides/adverse effects
- Oligopeptides/pharmacology
- Piperidines/adverse effects
- Piperidines/pharmacology
- Pituitary Gland, Anterior/drug effects
- Pituitary Gland, Anterior/metabolism
- Rats
- Rats, Wistar
- Receptors, Ghrelin/agonists
- Receptors, Ghrelin/antagonists & inhibitors
- Receptors, Ghrelin/metabolism
- Sarcolemma/drug effects
- Sarcolemma/metabolism
- Sarcoplasmic Reticulum/drug effects
- Sarcoplasmic Reticulum/metabolism
- Spiro Compounds/adverse effects
- Spiro Compounds/pharmacology
- Structure-Activity Relationship
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Affiliation(s)
- Antonella Liantonio
- Section of Pharmacology, Department of Pharmacy-Drug Sciences, University of Bari, Via Orabona, 4, Campus, I-70125 Bari, Italy.
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12
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Abstract
Diazoxide has been identified over the past 50years to have a number of physiological effects, including lowering the blood pressure and rectifying hypoglycemia. Today it is used clinically to treat these conditions. More recently, another important mode of action emerged: diazoxide has powerful protective properties against cardiac ischemia. The heart has intrinsic protective mechanisms against ischemia injury; one of which is ischemic preconditioning. Diazoxide mimics ischemic preconditioning. The purpose of this treatise is to review the literature in an attempt to identify the many effectors of diazoxide and discuss how they may contribute to diazoxide's cardioprotective properties. Particular emphasis is placed on the concentration ranges in which diazoxide affects its different targets and how this compares with the concentrations commonly used to study cardioprotection. It is concluded that diazoxide may have several potential effectors that may potentially contribute to cardioprotection, including KATP channels in the pancreas, smooth muscle, endothelium, neurons and the mitochondrial inner membrane. Diazoxide may also affect other ion channels and ATPases and may directly regulate mitochondrial energetics. It is possible that the success of diazoxide lies in this promiscuity and that the compound acts to rebalance multiple physiological processes during cardiac ischemia.
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Affiliation(s)
- William A Coetzee
- Department of Pediatrics, NYU School of Medicine, New York, NY 10016, United States; Department of Physiology & Neuroscience, NYU School of Medicine, New York, NY 10016, United States; Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY 10016, United States.
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13
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Muravyeva M, Sedlic F, Dolan N, Bosnjak ZJ, Stadnicka A. Preconditioning by isoflurane elicits mitochondrial protective mechanisms independent of sarcolemmal KATP channel in mouse cardiomyocytes. J Cardiovasc Pharmacol 2013; 61:369-77. [PMID: 23318991 PMCID: PMC3648596 DOI: 10.1097/fjc.0b013e318285f55b] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Cardiac mitochondria and the sarcolemmal (sarc)KATP channels contribute to cardioprotective signaling of anesthetic-induced preconditioning. Changes in mitochondrial bioenergetics influence the sarcolemmal ATP-sensitive K (sarcKATP) channel function, but whether this channel has impacts on mitochondria is uncertain. We used the mouse model with deleted pore-forming Kir6.2 subunit of sarcKATP channel (Kir6.2 KO) to investigate whether the functional sarcKATP channels are necessary for isoflurane activation of mitochondrial protective mechanisms. Ventricular cardiomyocytes were isolated from C57Bl6 wild-type (WT) and Kir6.2 KO mouse hearts. Flavoprotein autofluorescence, mitochondrial reactive oxygen species production, and mitochondrial membrane potential were monitored by laser-scanning confocal microscopy in intact cardiomyocytes. Cell survival was assessed using H2O2-induced stress. Isoflurane (0.5 mM) increased flavoprotein fluorescence to 180% ± 14% and 190% ± 15% and reactive oxygen species production to 118% ± 2% and 124% ± 6% of baseline in WT and Kir6.2 KO myocytes, respectively. Tetramethylrhodamine ethyl ester fluorescence decreased to 84% ± 6% in WT and to 86% ± 4% in Kir6.2 KO myocytes. This effect was abolished by 5HD. Pretreatment with isoflurane decreased the stress-induced cell death from 31% ± 1% to 21% ± 1% in WT and from 44% ± 2% to 35% ± 2% in Kir6.2 KO myocytes. In conclusion, Kir6.2 deletion increases the sensitivity of intact cardiomyocytes to oxidative stress, but does not alter the isoflurane-elicited protective mitochondrial mechanisms, suggesting independent roles for cardiac mitochondria and sarcKATP channels in anesthetic-induced preconditioning by isoflurane.
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Affiliation(s)
- Maria Muravyeva
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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14
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Spasov AA, Gurova NA, Kharitonova MV. [Structure and physiological role of NHE1 and pharmacological regulation of its activity]. Eksp Klin Farmakol 2013; 76:43-48. [PMID: 23461016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
This article summarizes results of preclinical and clinical trials concerning the effects of NHE1 inhibitors and prospects for their clinical application. NHE1 has been identified as the most abundant isoform of Na+/H+ exchanger in the heart of mammals. NHE1 regulates pH homeostasis, cell proliferation, migration, adhesion, and apoptosis. Ischemic activation of the NHE1 in myocardium results in intracellular calcium overload, which aggravates ischemic/reperfusion injury. In accordance with results of preclinical experimental studies, selective inhibition of the sarcolemmal NHE1 can delay progression of injury during ischemia, thereby reducing myocardial necrosis and improving recovery of ventricular function upon reperfusion. Inhibitors of NHE1, which can provide beneficial effect in the clinical treatment of these conditions, are currently under preclinical and clinical tests. At present, there are 481 NHE inhibitors known according to the Thomson Reuters Integrity database.
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15
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Kubasov IV, Arutiunian RS. [Investigation and analysis of chloride channels distribution over the surface and T-tubule membranes of frog skeletal muscle]. Ross Fiziol Zh Im I M Sechenova 2012; 98:1149-1158. [PMID: 23293819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Two types of muscle fibre integral currents (T1T and T2T) were recorded using narrow-tipped extracellular pipettes in isolated sartorius muscles of frog, Rana temporaria. T1T and T2T responses presumably were generated by currents originating in the muscle fibers sarcolemma (M-band region) or both sarcolemma and T-system (Z-line region), respectively, and differently responded to the selective blockade of C1C chloride channels with anthracene-9-carboxylic acid (9-AC). Eva- luation of the role of prolongation of T1T responses in generation of multiple peaks of the second phase (Na current) of T2T integral currents in muscle fibers are discussed.
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Chen LL, Zhang HH, Zheng J, Hu X, Kong W, Hu D, Wang SX, Zhang P. Resveratrol attenuates high-fat diet-induced insulin resistance by influencing skeletal muscle lipid transport and subsarcolemmal mitochondrial β-oxidation. Metabolism 2011; 60:1598-609. [PMID: 21632075 DOI: 10.1016/j.metabol.2011.04.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 04/08/2011] [Accepted: 04/08/2011] [Indexed: 12/21/2022]
Abstract
Although resveratrol (RES) is implicated in the regulation of insulin sensitivity in rodents, the exact mechanism underlying this effect remains unclear. Therefore, we sought to investigate how RES affects skeletal muscle lipid transportation and lipid oxidation of subsarcolemmal (SS) and intermyofibrillar (IMF) mitochondrial populations in high-fat diet (HFD)-induced insulin resistance (IR) rats. Systemic and skeletal muscle insulin sensitivity together with expressions of several genes related to mitochondrial biogenesis and skeletal muscle lipid transportation was studied in rats fed a normal diet, an HFD, and an HFD with intervention of RES for 8 weeks. Citrate synthase (CS), electron transport chain (ETC) activities, and several enzymes for mitochondrial β-oxidation were assessed in SS and IMF mitochondria from tibialis anterior muscle. The HFD-fed rats exhibited obvious systemic and skeletal muscle IR as well as intramuscular lipid accumulation. SIRT1 activity and expression of genes related to mitochondrial biogenesis were greatly declined, whereas the gene for lipid transportation, FAT/CD36, was upregulated (P < .05). Subsarcolemmal but not IMF mitochondria displayed lower CS, ETC, and β-oxidation activities. By contrast, RES treatment protected rats against diet-induced intramuscular lipid accumulation and IR, increased SIRT1 activity and mitochondrial biogenesis, and reverted the decline in SS mitochondrial CS and ETC activities. Importantly, although expression of FAT/CD36 was increased (11%, P < .05), activities of SS mitochondrial β-oxidation enzymes were largely enhanced (41%~67%, P < .05). This study suggests that RES ameliorates insulin sensitivity consistent with an improved balance between skeletal muscle lipid transportation and SS mitochondrial β-oxidation in HFD rats.
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Affiliation(s)
- Lu-Lu Chen
- Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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Biesmans L, Macquaide N, Heinzel FR, Bito V, Smith GL, Sipido KR. Subcellular heterogeneity of ryanodine receptor properties in ventricular myocytes with low T-tubule density. PLoS One 2011; 6:e25100. [PMID: 22022376 PMCID: PMC3192718 DOI: 10.1371/journal.pone.0025100] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Accepted: 08/26/2011] [Indexed: 11/19/2022] Open
Abstract
RATIONALE In ventricular myocytes of large mammals, not all ryanodine receptor (RyR) clusters are associated with T-tubules (TTs); this fraction increases with cellular remodeling after myocardial infarction (MI). OBJECTIVE To characterize RyR functional properties in relation to TT proximity, at baseline and after MI. METHODS Myocytes were isolated from left ventricle of healthy pigs (CTRL) or from the area adjacent to a myocardial infarction (MI). Ca(2+) transients were measured under whole-cell voltage clamp during confocal linescan imaging (fluo-3) and segmented according to proximity of TTs (sites of early Ca(2+) release, F>F(50) within 20 ms) or their absence (delayed areas). Spontaneous Ca(2+) release events during diastole, Ca(2+) sparks, reflecting RyR activity and properties, were subsequently assigned to either category. RESULTS In CTRL, spark frequency was higher in proximity of TTs, but spark duration was significantly shorter. Block of Na(+)/Ca(2+) exchanger (NCX) prolonged spark duration selectively near TTs, while block of Ca(2+) influx via Ca(2+) channels did not affect sparks properties. In MI, total spark mass was increased in line with higher SR Ca(2+) content. Extremely long sparks (>47.6 ms) occurred more frequently. The fraction of near-TT sparks was reduced; frequency increased mainly in delayed sites. Increased duration was seen in near-TT sparks only; Ca(2+) removal by NCX at the membrane was significantly lower in MI. CONCLUSION TT proximity modulates RyR cluster properties resulting in intracellular heterogeneity of diastolic spark activity. Remodeling in the area adjacent to MI differentially affects these RyR subpopulations. Reduction of the number of sparks near TTs and reduced local NCX removal limit cellular Ca(2+) loss and raise SR Ca(2+) content, but may promote Ca(2+) waves.
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Affiliation(s)
- Liesbeth Biesmans
- Laboratory of Experimental Cardiology, University of Leuven, Leuven, Belgium
| | - Niall Macquaide
- Laboratory of Experimental Cardiology, University of Leuven, Leuven, Belgium
- Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Frank R. Heinzel
- Laboratory of Experimental Cardiology, University of Leuven, Leuven, Belgium
- Division of Cardiology, Medical University of Graz, Graz, Austria
| | - Virginie Bito
- Laboratory of Experimental Cardiology, University of Leuven, Leuven, Belgium
| | - Godfrey L. Smith
- Faculty of Biomedical and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Karin R. Sipido
- Laboratory of Experimental Cardiology, University of Leuven, Leuven, Belgium
- * E-mail:
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18
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Danylovich IV, Danylovich GV, Kolomiietz' OV. [Effects of sodium nitroprusside and nitrite on ouabaine-sensitive Na+, K(+)-ATPase activity of myometrium smooth muscle]. Ukr Biokhim Zh (1999) 2010; 82:33-41. [PMID: 21805860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Effective inhibiting effect of sodium nitroprusside and nitrite on Na+, K(+)-ATPase enzymatic activity of miometrium sarcolemma fraction was shown. Seeming Ki was of micromolar and submicromolar magnitudes. Investigations with sodium nitroprusside demonstrated an uncompetitive inhibition for ATP (growth of affinity for ATP and decrease of maximal velocity) and mixed inhibition for cations (decrease of maximal velocity and activation of constant for K+). Inhibitory effect of ouabain was reduced in the presence of sodium nitroprusside; ditiothreitol prevented enzyme inactivation by sodium nitroprusside. Kinetic analysis of experimental results using ouabain and ditiothreitol suggests chemical modification of enzyme sulfhydryl groups. Resistant component of Na+, K(+)-ATPase activity, which is sensitive to the action of detergent digitonine, was observed. In comparative investigations with postnucleus fraction stimulating actions of sodium nitroprusside, sodium nitrite, cGMP (more enhance) were shown. Methylene blue (soluble guanilate-cyclase inhibitor) prevented the activation of Na+, K(+)-ATPase activity by sodium nitrite. We suppose that the way of enzyme activation is prevalent in the condition of the moderate formation of nitric oxide and in the absence of hyper(over)production of reactive oxygen species.
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19
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Ogneva IV, Altaeva EG. [Effects of nifedipine on the mechanical properties of sarcolemma and modulation of calcium accumulation dynamics in fibers of the rat soleus muscle under short-term hypogravity conditions]. Biofizika 2010; 55:918-924. [PMID: 21033362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
It has been shown that the modulation of the mechanical properties of sarcolemma by nifedipine may be related to the dynamics of accumulation of calcium ions under short-term rat hindlimb suspension. The basal calcium level was measured by the fluorescence probe Fluo-4AM, the transversal stiffness of different parts of the contractile apparatus and sarcolemma was estimated by atomic force microscopy, and the content of desmin was determined by gel electrophoresis with immunoblotting. It has been found that nifedipine has a protecting effect on muscle fibers under hypogravity by decreasing the degradation of desmin and proteins that determine the transversal stiffness of sarcolemma and the contractile apparatus, and the intensity of the increase in the basal calcium level. It was shown that the selective blocking of L-channels leads to an increase in the basal calcium level in intact soleus fibers. At the same time, the transversal stiffness of sarcolemma and the contractile apparatus increased. The mechanism of this increase is still unclear; however, it is assumed that it mediates the protecting action of nifedipine.
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Zhao G, Simpson RU. Membrane localization, Caveolin-3 association and rapid actions of vitamin D receptor in cardiac myocytes. Steroids 2010; 75:555-9. [PMID: 20015453 PMCID: PMC2885558 DOI: 10.1016/j.steroids.2009.12.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2009] [Revised: 12/03/2009] [Accepted: 12/07/2009] [Indexed: 11/26/2022]
Abstract
The active form of vitamin D, 1alpha, 25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), mediates both genomic and rapid non-genomic actions in heart cells. We have previously shown that the vitamin D receptor (VDR) is located in the t-tubular structure of cardiomyocytes. Here we show that VDR specifically interacts with Caveolin-3 in the t-tubules and sarcolemma of adult rat cardiac myocytes. Co-immunoprecipitation studies using VDR antibodies revealed that Caveolin-3 specifically co-precipitates with the VDR and similarly the VDR is co-precipitated with Caveolin-3 antibody. Confocal immuno-fluorescence microscopy analysis also showed co-localization of VDR and Caveolin-3 in t-tubules and sarcolemma. The non-genomic effects of the functional VDR were studied in electrically stimulated myocytes isolated from adult rat hearts. Sarcomere shortening and re-lengthening were measured in 1,25(OH)(2)D(3) treated cardiac myocytes. A 1nM treatment decreased peak shortening within minutes, suggesting a rapid effect through the membrane-bound VDR. This novel finding of the interaction between VDR and Caveolin-3 is fundamentally important in understanding 1,25(OH)(2)D(3) signal transduction in heart cells and provides further evidence that VDR plays a role in regulation of heart structure and function.
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Affiliation(s)
- Guisheng Zhao
- Department of Pharmacology, University of Michigan, School of Medicine, Ann Arbor, MI 48109, USA
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Danylovych HV, Danylovych IV, Horchev VF. [Registration of K(+)-equilibrium potential in myometrium cell plasma membrane and study of its modulation of NO(x) and H2O2, using flow cytometry method]. Ukr Biokhim Zh (1999) 2010; 82:52-61. [PMID: 20684228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Prospects of the use of flow cytometry analysis for investigation of forming K(+)- equilibrium membrane potential on the experimental model of myometrium plasma membrane vesicles in the presence of valinomycine using potential-sensitive probe of DiOC6(3). Transmembrane potential magnitude corresponds to magnitude by Nernst's equation. H2O2 and NO2-, probably, increase permeability of membrane for K+ and result in potential dissipation. Given effect is not shown for sodium nitroprusside. The obtained results confirm an assumption as to enhancing the passive transport for K+ through sarcolemma under the action of these substances, that can lead to membrane repolarisation and decline of the level of its excitability.
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Danylovych IV. [Hydrogen peroxide inhibits acetylcholinesterase of myometrium sarcolemma]. Ukr Biokhim Zh (1999) 2009; 81:32-38. [PMID: 20387632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The action of hydrogen peroxide on acetylcholinesterase enzymatic activity in myometrium sarcolemma fraction is investigated. Hydrogen peroxide (0.1-26 microM), depending on the concentration, suppressed the activity. Acetylcholinesterase proved to be highly sensitive to the action of H2O2, making Ki = 2.4 +/- 0.4 microM, nH = 0.65 +/- 0.08 (n = 4-5). It is established, that hydrogen peroxide in the range of 1.6 - 6.4 microM essentially reduce V(0,max) and K(M). In the presence of dithiothreitole (a reducer of SH-groups of the membrane surface) the investigated substance effect considerably decreased.
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Billman GE. The cardiac sarcolemmal ATP-sensitive potassium channel as a novel target for anti-arrhythmic therapy. Pharmacol Ther 2008; 120:54-70. [PMID: 18708091 DOI: 10.1016/j.pharmthera.2008.07.004] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Accepted: 07/14/2008] [Indexed: 12/25/2022]
Affiliation(s)
- George E Billman
- Department of Physiology and Cell Biology, The Ohio State University, 1645 Neil Avenue, Columbus, OH 43210-1218, USA.
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Danylovych IV, Karakhim SO. [The action of nitrite-anions and hydrogen peroxide on surface properties of the smooth muscle plasmatic membrane]. Ukr Biokhim Zh (1999) 2008; 80:52-61. [PMID: 19248618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
In the presence of vesicular preparations of sarcolemma (near 70% reverse cytoplasmic sideways inward) fluorescence of ANS--1-(fenilamino)-8-naftylamine--rises more than 10 times. In the conditions of increase of concentration of sodium nitrite and hydrogen peroxide from 1 to 5 microM the probe fluorescence diminishes. Extinguishing of ANS fluorescence under the action of nitrite anions can be explained by chemical modification of the positively charged superficial groups (amino- and sulfhydrile). It will result in the decrease of amounts of local "+"-charges on a membrane, proper decrease of fastening ANS with a membrane and fluorescence extinguishing. H2O2 is able to oxidize superficial -SH-groups which carry a partial positive charge. Consequently a decrease of general amount of fixed "+" charges on a membrane, diminishing of ANS fastening with sarcolemma and the proper fluorescence extinguishing takes place. Probed and calculated by the method "ion beats" superficial closeness of charges of vesicular preparations makes 2.3 +/- 0.1 mC/m2. At the action of 50 microM sodium nitrite and hydrogen peroxide it diminishes to 2.0 +/- 0.1 mC/m2 and 1.7 +/- 0.07 mC/m2 accordingly. The less effective action of NaNO2 can be determined by the influence of Na+ on the superficial field of membrane. With the purpose to confirm the previous suppositions we used the method of laser-correlation spectroscopy, that registered the mean value of hydrodynamic diameter (GD) of vesicules and their division by sizes. Middle GD makes in control 327 +/- 16 nm, and GD which is most often met in population--291 +/- 11 nm. Adding of nitrite anions to the system in a growing concentration results in the substantial decline of GD of both all the membrane population and of plasma vesicules. Analogous results are obtained in the case of H2O2. In the presence of specific modifiers of sulfhydrile- and aminogroup of membrane surface (DTT and TNBS) the decline of GD under the action of nitrite anions or hydrogen peroxide is not observed, or diminishes substantially. Consequently, the diminishing of GD in our system under the action of the probed compounds can be related to chemical modification of amino or/and sulfhydrile groups of membrane surface which complements and confirms experiments with ANS. Diminishing of density of superficial positive charges is possible under the condition of the action of nitrogen oxides and hydrogen peroxide on the membrane can result in strengthening of cations interaction with a membrane and, in principle, will influence their reception and transport.
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Abstract
In dystrophin-deficient fibers of mdx mice and in Duchenne dystrophy, the lack of dystrophin leads to sarcolemma breakdown and muscle degeneration. We verified that cromolyn, a mast-cell stabilizer agent, stabilized dystrophic muscle fibers using Evans blue dye as a marker of sarcolemma leakiness. Mdx mice (n=8; 14 days of age) received daily intraperitoneal injections of cromolyn (50 mg/kg body weight) for 15 days. Untreated mdx mice (n=8) were injected with saline. Cryostat cross-sections of the sternomastoid, tibialis anterior, and diaphragm muscles were stained with hematoxylin and eosin. Cromolyn dramatically reduced Evans blue dye-positive fibers in all muscles (P<0.05; Student's t-test) and led to a significant increase in the percentage of fibers with peripheral nuclei. This study supports the protective effects of cromolyn in dystrophic muscles and further indicates its action against muscle fiber leakiness in muscles that are differently affected by the lack of dystrophin.
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MESH Headings
- Animals
- Anti-Asthmatic Agents/pharmacology
- Anti-Asthmatic Agents/therapeutic use
- Cell Membrane Permeability/drug effects
- Cell Membrane Permeability/physiology
- Cromolyn Sodium/pharmacology
- Cromolyn Sodium/therapeutic use
- Disease Models, Animal
- Dystrophin/deficiency
- Dystrophin/genetics
- Female
- Ion Channels/drug effects
- Ion Channels/genetics
- Ion Channels/metabolism
- Ions/metabolism
- Male
- Mast Cells/drug effects
- Mast Cells/immunology
- Mice
- Mice, Inbred mdx
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Skeletal/pathology
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Muscular Dystrophy, Animal/drug therapy
- Muscular Dystrophy, Animal/metabolism
- Muscular Dystrophy, Animal/pathology
- Muscular Dystrophy, Duchenne/drug therapy
- Muscular Dystrophy, Duchenne/metabolism
- Muscular Dystrophy, Duchenne/pathology
- Sarcolemma/drug effects
- Sarcolemma/genetics
- Sarcolemma/metabolism
- Treatment Outcome
- Water-Electrolyte Balance/drug effects
- Water-Electrolyte Balance/genetics
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Affiliation(s)
- Maria Julia Marques
- Departamento de Anatomia, Instituto de Biologia, Universidade Estadual de Campinas, Campinas, São Paulo 13083-970, Brazil.
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Vajda S, Baczkó I, Leprán I. Selective cardiac plasma-membrane KATP channel inhibition is defibrillatory and improves survival during acute myocardial ischemia and reperfusion. Eur J Pharmacol 2007; 577:115-23. [PMID: 17904545 DOI: 10.1016/j.ejphar.2007.08.016] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2006] [Revised: 08/03/2007] [Accepted: 08/13/2007] [Indexed: 11/19/2022]
Abstract
ATP-dependent potassium channels (K(ATP)) have been implicated in cardioprotection both during myocardial ischemia and reperfusion. We compared the effect of a non-selective K(ATP) inhibitor glibenclamide, a selective mitochondrial K(ATP) inhibitor 5-hydroxy-decanoate (5-HD) and a selective sarcolemmal K(ATP) blocker HMR 1883, on survival and incidence of arrhythmias during myocardial ischemia in conscious, and during ischemia-reperfusion in pentobarbitone anesthetized rats. Glibenclamide (5 mg/kg i.p.) or HMR 1883 (3 mg/kg i.v.) reduced ischemia-induced irreversible ventricular fibrillation and improved survival during myocardial ischemia (64% and 61% vs. 23% in controls, respectively). 5-HD (5 mg/kg i.v.) did not influence survival and the incidence of ventricular arrhythmias. The incidence of reperfusion-induced arrhythmias was reduced by both glibenclamide and HMR 1883 (3 or 10 mg/kg) resulting in improved survival during reperfusion (81%, 82% and 96% vs. 24% in controls, respectively) in anesthetized rats. 5-HD did not reduce the incidence of lethal reperfusion arrhythmias. Glibenclamide and HMR 1883 prolonged (89+/-4.6 and 89+/-4.9 ms vs. 60+/-2.4 ms in controls), while 5-HD did not change the QT interval. In conclusion, inhibition of sarcolemmal K(ATP) reduces the incidence of lethal ventricular arrhythmias and improves survival both during acute myocardial ischemia and reperfusion in rats. This beneficial effect correlates with the prolongation of repolarization. Inhibition of mitochondrial K(ATP) does not improve survival or reduce the occurrence of ischemia and/or reperfusion-induced arrhythmias and does not prolong the QT interval. The present results also suggest that the antiarrhythmic effect of K(ATP) inhibitors is not influenced by pentobarbitone anesthesia.
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Affiliation(s)
- Szilvia Vajda
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, Albert Szent-Györgyi Medical Centre, University of Szeged, Szeged, Hungary
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Rocha T, de Souza BM, Palma MS, da Cruz-Höfling MA. Myotoxic effects of mastoparan from Polybia paulista (Hymenoptera, Epiponini) wasp venom in mice skeletal muscle. Toxicon 2007; 50:589-99. [PMID: 17572466 DOI: 10.1016/j.toxicon.2007.05.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Revised: 05/02/2007] [Accepted: 05/08/2007] [Indexed: 11/28/2022]
Abstract
In a previous study, we showed that the Polybia paulista wasp venom causes strong myonecrosis. This study was undertaken to characterize the myotoxic potency of mastoparan (Polybia-MPII) isolated from venom (0.25 microg/microl) and injected in the tibial anterior (TA) muscle (i.m.) of Balb/c mice. The time course of the changes was followed at muscle degenerative (3 and 24h) and regenerative (3, 7, and 21 days) periods (n=6) after injection and compared to matched controls by calculation of the percentage of cross-sectional area affected and determination of creatine kinase (CK) activity (n=10). The results showed that although MP was strongly myotoxic, its capacity for regeneration was maintained high. Since the extent of tissue damage was not correlated with the CK serum levels, which remained very low, we raised the hypothesis that the enzyme underwent denaturation by the peptide. Evidence suggested that MP induced the death of TA fibers by necrosis and apoptosis and had the sarcolemma as its primordial target. Given its amphiphilic polycationic nature and based on the vast spectrum of functions attributed to the peptide, we suggest that MP interaction with cell membrane impaired the phosphorylation of dystrophin essential for sarcolemma mechanical stability, and disturbed Ca2+ mobilization with obvious implications on sarcoplasmic reticulum and mitochondrial functioning.
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Affiliation(s)
- Thalita Rocha
- Department of Histology and Embryology, Institute of Biology, P.O. Box 6109, State University of Campinas, Campinas, SP 13083-970, Brazil
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29
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Tricarico D, Mele A, Liss B, Ashcroft FM, Lundquist AL, Desai RR, George AL, Conte Camerino D. Reduced expression of Kir6.2/SUR2A subunits explains KATP deficiency in K+-depleted rats. Neuromuscul Disord 2007; 18:74-80. [PMID: 17825556 DOI: 10.1016/j.nmd.2007.07.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2007] [Revised: 05/17/2007] [Accepted: 07/25/2007] [Indexed: 11/24/2022]
Abstract
We investigated on the mechanism responsible for the reduced ATP-sensitive K(+)(K(ATP)) channel activity recorded from skeletal muscle of K(+)-depleted rats. Patch-clamp and gene expression measurements of K(ATP) channel subunits were performed. A down-regulation of the K(ATP) channel subunits Kir6.2(-70%) and SUR2A(-46%) in skeletal muscles of K(+)-depleted rats but no changes in the expression of Kir6.1, SUR1 and SUR2B subunits were observed. A reduced K(ATP) channel currents of -69.5% in K(+)-depleted rats was observed. The Kir6.2/SUR2A-B agonist cromakalim showed similar potency in activating the K(ATP) channels of normokalaemic and K(+)-depleted rats but reduced efficacy in K(+)-depleted rats. The Kir6.2/SUR1-2B agonist diazoxide activated K(ATP) channels in normokalaemic and K(+)-depleted rats with equal potency and efficacy. The down-regulation of the Kir6.2 explains the reduced K(ATP) channel activity in K(+)-depleted rats. The lower expression of SUR2A explains the reduced efficacy of cromakalim; preserved SUR1 expression accounts for the efficacy of diazoxide. Kir6.2/SUR2A deficiency is associated with impaired muscle function in K(+)-depleted rats and in hypoPP.
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Affiliation(s)
- Domenico Tricarico
- Department of Pharmacobiology, Faculty of Pharmacy, University of Bari, via Orabona no 4, 70120 Bari, Italy.
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30
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Chen F, De Diego C, Xie LH, Yang JH, Klitzner TS, Weiss JN. Effects of metabolic inhibition on conduction, Ca transients, and arrhythmia vulnerability in embryonic mouse hearts. Am J Physiol Heart Circ Physiol 2007; 293:H2472-8. [PMID: 17660398 DOI: 10.1152/ajpheart.00359.2007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Developing myocardium is more dependent on glycolysis than adult myocardium, yet the effects of selectively inhibiting glycolysis versus oxidative phosphorylation on embryonic heart function have not been well characterized. Accordingly, we investigated how selective metabolic inhibition affects membrane voltage and intracellular Ca (Ca(i)) transients in embryonic mouse hearts, including their susceptibility to arrhythmias. A total of 136 isolated embryonic mouse hearts were exposed to either 1) 2-deoxyglucose (2DG; 10 mM) or iodoacetate (IAA; 0.1 mM) with 10 mM pyruvate in place of glucose to selectively inhibit glycolysis or 2) the mitochondrial uncoupler protonophore carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone (FCCP; 500 nM) with 10 mM glucose present to selectively inhibit oxidative phosphorylation. Using confocal imaging, we found that mitochondrial membrane potential monitored with tetramethylrhodamine methyl ester (200 nM) remained stable with 2DG or IAA but depolarized within 5 min after exposure to FCCP. IAA and FCCP decreased heart rate, inhibited Ca(i) transient amplitude, shortened action potential duration at 80% repolarization (APD(80)), and prolonged atrioventricular conduction time to similar extents. Although 2DG decreased heart rate and Ca(i) transient amplitude, it did not significantly affect APD(80) and AV conduction time. In addition, spontaneous arrhythmias occurred in 77 of 136 embryonic hearts (57%) after exposure to IAA (28/53) or FCCP (49/83). There were no significant differences in the types or incidence of arrhythmias induced by IAA and FCCP. These data support the idea that both glycolysis and oxidative phosphorylation play critical metabolic roles in regulating cardiac function in the embryonic mouse heart.
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Affiliation(s)
- Fuhua Chen
- Cardiovascular Research Laboratory, David Geffen School of Medicine at University of California, Los Angeles, California 90095-1760, USA
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31
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Volkov EM, Sabirova AR, Nurullin LF, Zefirov AL. Functional heterogeneity of the "transporter" of electrogenic ionic pump of the Lumbricus terrestris somatic myocyte membrane. Bull Exp Biol Med 2007; 142:720-2. [PMID: 17603680 DOI: 10.1007/s10517-006-0461-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Potential created by electrogenic ionic pumps under conditions of maximum activation in a warm standard ionic medium with K(+) after preincubation in cold potassium-free solution has two components: a higher ouabaine-insensitive "stationary" component, and a lower "regulatory" component sensitive to ouabaine, furosemide, and removal of Cl(-) or Ca(2+) from the medium. Functional heterogeneity of electrogenic ionic pumps is hypothesized implying the existence of two components: "stationary" (not regulated extracellularly) and "regulatory" (controlled and directly related to active Cl(-) transfer).
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Affiliation(s)
- E M Volkov
- Kazan State Medical University, Russian Ministry of Health, Russia.
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32
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Cairns SP, Chin ER, Renaud JM. Stimulation pulse characteristics and electrode configuration determine site of excitation in isolated mammalian skeletal muscle: implications for fatigue. J Appl Physiol (1985) 2007; 103:359-68. [PMID: 17412789 DOI: 10.1152/japplphysiol.01267.2006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We examined whether electrical field stimulation with varying characteristics could excite isolated mammalian skeletal muscle through different sites. Supramaximal (20-V, 0.1-ms) pulse stimulation with transverse wire or parallel plate electrodes evoked similar forces in nonfatigued slow-twitch soleus and fast-twitch extensor digitorum longus (EDL) muscles from mice. d-tubocurarine shifted the twitch force-stimulation strength relationship toward higher pulse strengths with both electrode configurations in soleus muscle, suggesting that weaker pulses excite muscle via neuromuscular transmission. With wire stimulation, movement of the recording electrode along the muscle caused a delay between the stimulus artifact and the peak of the action potential, consistent with action potential propagation along the sarcolemma. TTX abolished all contractions evoked with 20-V, 0.1-ms pulses, suggesting that excitation occurred via voltage-dependent Na+ channels and, hence, muscle action potentials. TTX did not prevent force development with ≥0.4-ms pulses in soleus or 1-ms pulses in EDL muscle. Furthermore, myoplasmic Ca2+ (i.e., the fura 2 ratio) and sarcomere shortening were greater during tetanic stimulation with 2.0-ms than with 0.5-ms pulses in flexor digitorum brevis fibers from rats. TTX prevented all shortening and Ca2+ release with 0.5-ms, but not 2.0-ms, pulses, indicating that longer pulses can directly trigger Ca2+ release. Hence, proper interpretation of mechanistic studies requires precise understanding of how muscles are excited; otherwise, incorrect conclusions can be made. Using this new understanding, we showed that disrupted propagation of action potentials along the surface membrane is a major cause of fatigue in soleus muscle that is focally and continuously stimulated at 125 Hz.
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Affiliation(s)
- Simeon P Cairns
- Institute of Sport and Recreation Research New Zealand, Faculty of Health and Environmental Science, Auckland University of Technology, Auckland, New Zealand.
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33
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Silva HS, Kapela A, Tsoukias NM. A mathematical model of plasma membrane electrophysiology and calcium dynamics in vascular endothelial cells. Am J Physiol Cell Physiol 2007; 293:C277-93. [PMID: 17459942 DOI: 10.1152/ajpcell.00542.2006] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vascular endothelial cells (ECs) modulate smooth muscle cell (SMC) contractility, assisting in vascular tone regulation. Cytosolic Ca2+ concentration ([Ca2+]i) and membrane potential ( Vm) play important roles in this process by controlling EC-dependent vasoactive signals and intercellular communication. The present mathematical model integrates plasmalemma electrophysiology and Ca2+ dynamics to investigate EC responses to different stimuli and the controversial relationship between [Ca2+]i and Vm. The model contains descriptions for the intracellular balance of major ionic species and the release of Ca2+ from intracellular stores. It also expands previous formulations by including more detailed transmembrane current descriptions. The model reproduces Vm responses to volume-regulated anion channel (VRAC) blockers and extracellular K+ concentration ([K+]o) challenges, predicting 1) that Vm changes upon VRAC blockade are [K+]o dependent and 2) a biphasic response of Vm to increasing [K+]o. Simulations of agonist-induced Ca2+ mobilization replicate experiments under control and Vm hyperpolarization blockade conditions. They show that peak [Ca2+]i is governed by store Ca2+ release while Ca2+ influx (and consequently Vm) impacts more the resting and plateau [Ca2+]i. The Vm sensitivity of rest and plateau [Ca2+]i is dictated by a [Ca2+]i “buffering” system capable of masking the Vm-dependent transmembrane Ca2+ influx. The model predicts plasma membrane Ca2+-ATPase and Ca2+ permeability as main players in this process. The heterogeneous Vm impact on [Ca2+]i may elucidate conflicting reports on how Vm influences EC Ca2+. The present study forms the basis for the development of multicellular EC-SMC models that can assist in understanding vascular autoregulation in health and disease.
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Affiliation(s)
- Haroldo S Silva
- Dept. of Biomedical Engineering, Florida International University, 10555 W. Flagler St., TEC 2674, Miami, FL 33174, USA
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34
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Saini HK, Dhalla NS. Sarcolemmal cation channels and exchangers modify the increase in intracellular calcium in cardiomyocytes on inhibiting Na+-K+-ATPase. Am J Physiol Heart Circ Physiol 2007; 293:H169-81. [PMID: 17322410 DOI: 10.1152/ajpheart.00007.2007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Although inhibition of the sarcolemmal (SL) Na+-K+-ATPase is known to cause an increase in the intracellular concentration of Ca2+([Ca2+]i) by stimulating the SL Na+/Ca2+exchanger (NCX), the involvement of other SL sites in inducing this increase in [Ca2+]iis not fully understood. Isolated rat cardiomyocytes were treated with or without different agents that modify Ca2+movements by affecting various SL sites and were then exposed to ouabain. Ouabain was observed to increase the basal levels of both [Ca2+]iand intracellular Na+concentration ([Na+]i) as well as to augment the KCl-induced increases in both [Ca2+]iand [Na+]iin a concentration-dependent manner. The ouabain-induced changes in [Na+]iand [Ca2+]iwere attenuated by treatment with inhibitors of SL Na+/H+exchanger and SL Na+channels. Both the ouabain-induced increase in basal [Ca2+]iand augmentation of the KCl response were markedly decreased when cardiomyocytes were exposed to 0–10 mM Na+. Inhibitors of SL NCX depressed but decreasing extracellular Na+from 105–35 mM augmented the ouabain-induced increase in basal [Ca2+]iand the KCl response. Not only was the increase in [Ca2+]iby ouabain dependent on the extracellular Ca2+concentration, but it was also attenuated by inhibitors of SL L-type Ca2+channels and store-operated Ca2+channels (SOC). Unlike the SL L-type Ca2+-channel blocker, the blockers of SL Na+channel and SL SOC, when used in combination with SL NCX inhibitor, showed additive effects in reducing the ouabain-induced increase in basal [Ca2+]i. These results support the view that in addition to SL NCX, SL L-type Ca2+channels and SL SOC may be involved in raising [Ca2+]ion inhibition of the SL Na+-K+-ATPase by ouabain. Furthermore, both SL Na+/H+exchanger and Na+channels play a critical role in the ouabain-induced Ca2+increase in cardiomyocytes.
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Affiliation(s)
- Harjot K Saini
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, 351 Tache Avenue, Winnipeg, Manitoba, Canada
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35
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Abstract
The Na+/K+-ATPase (NKA) is the main route for Na+ extrusion from cardiac myocytes. Different NKA α-subunit isoforms are present in the heart. NKA-α1 is predominant, although there is a variable amount of NKA-α2 in adult ventricular myocytes of most species. It has been proposed that NKA-α2 is localized mainly in T-tubules (TT), where it could regulate local Na+/Ca2+ exchange and thus cardiac myocyte Ca2+. However, there is controversy as to where NKA-α1 vs. NKA-α2 are localized in ventricular myocytes. Here, we assess the TT vs. external sarcolemma (ESL) distribution functionally using formamide-induced detubulation of rat ventricular myocytes, NKA current (IPump) measurements and the different ouabain sensitivity of NKA-α1 (low) and NKA-α2 (high) in rat heart. Ouabain-dependent IPump inhibition in control myocytes indicates a high-affinity NKA isoform (NKA-α2, K1/2 = 0.38 ± 0.16 μM) that accounts for 29.5 ± 1.3% of IPump and a low-affinity isoform (NKA-α1, K1/2 = 141 ± 17 μM) that accounts for 70.5% of IPump. Detubulation decreased cell capacitance from 164 ± 6 to 120 ± 8 pF and reduced IPump density from 1.24 ± 0.05 to 1.02 ± 0.05 pA/pF, indicating that the functional density of NKA is significantly higher in TT vs. ESL. In detubulated myocytes, NKA-α2 accounted for only 18.2 ± 1.1% of IPump. Thus, ∼63% of IPump generated by NKA-α2 is from the TT (although TT are only 27% of the total sarcolemma), and the NKA-α2/NKA-α1 ratio in TT is significantly higher than in the ESL. The functional density of NKA-α2 is ∼4.5 times higher in the T-tubules vs. ESL, whereas NKA-α1 is almost uniformly distributed between the TT and ESL.
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Affiliation(s)
- Sanda Despa
- Dept. of Physiology, Loyola University Chicago, Stritch School of Medicine, 2160 South First Ave., Maywood, IL 60153, USA
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36
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Abstract
The phospholipases associated with the cardiac sarcolemmal (SL) membrane hydrolyze specific membrane phospholipids to generate important lipid signaling molecules, which are known to influence normal cardiac function. However, impairment of the phospholipases and their related signaling events may be contributory factors in altering cardiac function of the diseased myocardium. The identification of the changes in such signaling systems as well as understanding the contribution of phospholipid-signaling pathways to the pathophysiology of heart disease are rapidly emerging areas of research in this field. In this paper, I provide an overview of the role of phospholipid-mediated signal transduction processes in cardiac hypertrophy and congestive heart failure, diabetic cardiomyopathy, as well as in ischemia-reperfusion. From the cumulative evidence presented, it is suggested that phospholipid-mediated signal transduction processes could serve as novel targets for the treatment of the different types of heart disease.
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Affiliation(s)
- Paramjit S Tappia
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre and Department of Human Nutritional Sciences, University of Manitoba, Winnipeg, MB, R2H 2A6, Canada
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37
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Gordon SE, Westerkamp CM, Savage KJ, Hickner RC, George SC, Fick CA, McCormick KM. Basal, but not overload-induced, myonuclear addition is attenuated by NG-nitro-l-arginine methyl ester (l-NAME) administration. Can J Physiol Pharmacol 2007; 85:646-51. [PMID: 17823627 DOI: 10.1139/y07-024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this study was to examine the effect of blocking nitric oxide synthase (NOS) activity via NG-nitro-l-arginine methyl ester (l-NAME) on myonuclear addition in skeletal muscle under basal and overloaded conditions. Female Sprague–Dawley rats (approx. 220 g) were placed into 1 of the following 4 groups (n = 7–9/group): 7-day skeletal muscle overload (O), sham operation (S), skeletal muscle overload with l-NAME treatment (OLN), and sham operation with l-NAME treatment (SLN). Plantaris muscles were overloaded via bilateral surgical ablation of the gastrocnemius muscles and l-NAME (0.75 mg/mL) was administered in the animals’ daily drinking water starting 2 days prior to surgery and continued until sacrifice. Myonuclear addition was assessed as subsarcolemmal incorporation of nuclei labeled with 5-bromo-2′-deoxyuridine (approx. 25 mg·(kg body mass)–1·day–1) delivered via osmotic pump during the overload period. As expected, muscle wet mass, total protein content, fiber cross-sectional area, and myonuclear addition were significantly higher (p ≤ 0.05) in O vs. S; however, only the increase in wet mass and total protein content (per body mass) were attenuated by l-NAME administration. Interestingly, l-NAME significantly reduced myonuclear addition by 75% in nonoverloaded muscles (SLN vs. S). Muscle hepatocyte growth factor protein content increased with overload, but was unaffected by l-NAME in either loading state. These data indicate that NOS inhibition in rat plantaris muscle attenuates myonuclear addition under basal, but not overloaded, conditions.
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MESH Headings
- Administration, Oral
- Animals
- Bromodeoxyuridine/metabolism
- Cell Nucleus/drug effects
- Cell Nucleus/metabolism
- Cell Proliferation/drug effects
- Drinking
- Enzyme Inhibitors/administration & dosage
- Enzyme Inhibitors/pharmacology
- Female
- Hepatocyte Growth Factor/metabolism
- Immunohistochemistry
- Intranuclear Inclusion Bodies/drug effects
- Intranuclear Inclusion Bodies/metabolism
- Muscle Fibers, Skeletal/cytology
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/metabolism
- Muscle Proteins/metabolism
- Muscle, Skeletal/cytology
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- NG-Nitroarginine Methyl Ester/administration & dosage
- NG-Nitroarginine Methyl Ester/pharmacology
- Nitric Oxide Synthase/antagonists & inhibitors
- Rats
- Rats, Sprague-Dawley
- Sarcolemma/drug effects
- Sarcolemma/metabolism
- Satellite Cells, Skeletal Muscle/cytology
- Satellite Cells, Skeletal Muscle/drug effects
- Satellite Cells, Skeletal Muscle/metabolism
- Time Factors
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Affiliation(s)
- Scott E Gordon
- Human Performance Laboratory, Department of Exercise and Sport Science, East Carolina University, Greenville, NC 27858, USA.
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38
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Gross ER, Hsu AK, Gross GJ. GSK3β inhibition and KATP channel opening mediate acute opioid-induced cardioprotection at reperfusion. Basic Res Cardiol 2007; 102:341-9. [PMID: 17450314 DOI: 10.1007/s00395-007-0651-6] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2007] [Revised: 03/01/2007] [Accepted: 03/05/2007] [Indexed: 10/23/2022]
Abstract
Both glycogen synthase kinase 3beta (GSK3beta) and the ATP-dependant potassium channel (K(ATP)) mediate opioid-induced cardioprotection (OIC). However, whether direct K(ATP) channel openers induce cardioprotection prior to reperfusion and their signaling cascade position with respect to GSK3beta inhibition is unknown. Therefore, we investigated the role of K(ATP) channel opening at reperfusion in OIC, and the interaction between the GSK signaling axis and K(ATP) channels in cardioprotection.Male Sprague-Dawley rats underwent 30 minutes ischemia with 2 hours of reperfusion and infarct size was determined. Rats given the nonselective opioid agonist, morphine (0.3 mg/kg), or the selective delta opioid agonist, BW373U86 (1.0 mg/kg), 5 minutes prior to reperfusion reduced infarct size (40.3+/-1.6*, 39.7+/-1.9* versus 60.0+/-1.1%, respectively, * P<0.001%). This protection was abrogated with prior administration of the putative sarcolemmal K(ATP) antagonist, HMR-1098 (6 mg/kg), or the putative mitochondrial K(ATP) antagonist, 5-HD (10 mg/kg). The putative sK(ATP) channel opener, P-1075 (1microg/kg) or the putative mK(ATP) channel opener, BMS-191095 (1 mg/kg) given 5 minutes prior to reperfusion also reduced infarct size (41.8+/-2.4*, 43.4+/-1.4*) and protection was abrogated by prior administration of the PI3k inhibitor wortmannin (60.0+/-1.7, 64.0+/-2.6%, respectively, * P<0.001). Cardioprotection afforded by the GSK inhibitor SB216763 (0.6 mg/kg) given 5 minutes prior to reperfusion was also partially blocked by either HMR or 5-HD and completely blocked when HMR and 5-HD were given in combination (40.8+/-1.6*, 50.4+/-1.6;; 49.4+/-1.7;, 61.6+/-1.6%, respectively, * or ; P<0.001). These data indicate that both the sK(ATP) and mK(ATP) channel are involved in acute OIC and the GSK signaling axis regulates cardioprotection via K(ATP) channel opening.
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Affiliation(s)
- Eric R Gross
- Medical College of Wisconsin, Dept. of Pharmacology and Toxicology, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
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39
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Hall TE, Bryson-Richardson RJ, Berger S, Jacoby AS, Cole NJ, Hollway GE, Berger J, Currie PD. The zebrafish candyfloss mutant implicates extracellular matrix adhesion failure in laminin alpha2-deficient congenital muscular dystrophy. Proc Natl Acad Sci U S A 2007; 104:7092-7. [PMID: 17438294 PMCID: PMC1855385 DOI: 10.1073/pnas.0700942104] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mutations in the human laminin alpha2 (LAMA2) gene result in the most common form of congenital muscular dystrophy (MDC1A). There are currently three models for the molecular basis of cellular pathology in MDC1A: (i) lack of LAMA2 leads to sarcolemmal weakness and failure, followed by cellular necrosis, as is the case in Duchenne muscular dystrophy (DMD); (ii) loss of LAMA2-mediated signaling during the development and maintenance of muscle tissue results in myoblast proliferation and fusion defects; (iii) loss of LAMA2 from the basement membrane of the Schwann cells surrounding the peripheral nerves results in a lack of motor stimulation, leading to effective denervation atrophy. Here we show that the degenerative muscle phenotype in the zebrafish dystrophic mutant, candyfloss (caf) results from mutations in the laminin alpha2 (lama2) gene. In vivo time-lapse analysis of mechanically loaded fibers and membrane permeability assays suggest that, unlike DMD, fiber detachment is not initially associated with sarcolemmal rupture. Early muscle formation and myoblast fusion are normal, indicating that any deficiency in early Lama2 signaling does not lead to muscle pathology. In addition, innervation by the primary motor neurons is unaffected, and fiber detachment stems from muscle contraction, demonstrating that muscle atrophy through lack of motor neuron activity does not contribute to pathology in this system. Using these and other analyses, we present a model of lama2 function where fiber detachment external to the sarcolemma is mechanically induced, and retracted fibers with uncompromised membranes undergo subsequent apoptosis.
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MESH Headings
- Adhesiveness/drug effects
- Alleles
- Amino Acid Sequence
- Animals
- Base Sequence
- Cell Death/drug effects
- Codon, Nonsense/genetics
- Embryo, Nonmammalian/cytology
- Embryo, Nonmammalian/drug effects
- Embryo, Nonmammalian/innervation
- Embryo, Nonmammalian/ultrastructure
- Extracellular Matrix/drug effects
- Extracellular Matrix/metabolism
- Gene Expression Regulation/drug effects
- Intercellular Junctions/drug effects
- Intercellular Junctions/ultrastructure
- Laminin/chemistry
- Laminin/deficiency
- Laminin/genetics
- Laminin/metabolism
- Molecular Sequence Data
- Motor Activity/drug effects
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/pathology
- Muscular Dystrophy, Animal/congenital
- Mutant Proteins/metabolism
- Oligonucleotides, Antisense/pharmacology
- Open Reading Frames/genetics
- Sarcolemma/drug effects
- Sarcolemma/pathology
- Sequence Homology, Amino Acid
- Zebrafish/abnormalities
- Zebrafish/embryology
- Zebrafish Proteins/metabolism
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Affiliation(s)
- Thomas E. Hall
- The Victor Chang Cardiac Research Institute, 384 Victoria Street, Darlinghurst, Sydney NSW 2010, Australia
| | | | - Silke Berger
- The Victor Chang Cardiac Research Institute, 384 Victoria Street, Darlinghurst, Sydney NSW 2010, Australia
| | - Arie S. Jacoby
- The Victor Chang Cardiac Research Institute, 384 Victoria Street, Darlinghurst, Sydney NSW 2010, Australia
| | - Nicholas J. Cole
- The Victor Chang Cardiac Research Institute, 384 Victoria Street, Darlinghurst, Sydney NSW 2010, Australia
| | - Georgina E. Hollway
- The Victor Chang Cardiac Research Institute, 384 Victoria Street, Darlinghurst, Sydney NSW 2010, Australia
| | - Joachim Berger
- The Victor Chang Cardiac Research Institute, 384 Victoria Street, Darlinghurst, Sydney NSW 2010, Australia
| | - Peter D. Currie
- The Victor Chang Cardiac Research Institute, 384 Victoria Street, Darlinghurst, Sydney NSW 2010, Australia
- *To whom correspondence should be addressed. E-mail:
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40
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Wang S, Radhakrishnan J, Ayoub IM, Kolarova JD, Taglieri DM, Gazmuri RJ. Limiting sarcolemmal Na+ entry during resuscitation from ventricular fibrillation prevents excess mitochondrial Ca2+ accumulation and attenuates myocardial injury. J Appl Physiol (1985) 2007; 103:55-65. [PMID: 17431086 DOI: 10.1152/japplphysiol.01167.2006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND intracellular Na+ accumulation during ischemia and reperfusion leads to cytosolic Ca2+ overload through reverse-mode operation of the sarcolemmal Na+ -Ca2+ exchanger. Cytosolic Ca2+ accumulation promotes mitochondrial Ca2+ (Ca2+ m) overload, leading to mitochondrial injury. We investigated whether limiting sarcolemmal Na+ entry during resuscitation from ventricular fibrillation (VF) attenuates Ca2+ m overload and lessens myocardial dysfunction in a rat model of VF and closed-chest resuscitation. METHODS hearts were harvested from 10 groups of 6 rats each representing baseline, 15 min of untreated VF, 15 min of VF with chest compression given for the last 5 min (VF/CC), and 60 min postresuscitation (PR). VF/CC and PR included four groups each randomized to receive before starting chest compression the new NHE-1 inhibitor AVE4454B (1.0 mg/kg), the Na+ channel blocker lidocaine (5.0 mg/kg), their combination, or vehicle control. The left ventricle was processed for intracellular Na+ and Ca2+ m measurements. RESULTS limiting sarcolemmal Na+ entry attenuated cytosolic Na+ increase during VF/CC and the PR phase and prevented Ca2+ m overload yielding levels that corresponded to 77% and 71% of control hearts at VF/CC and PR, without differences among specific Na+ -limiting interventions. Limiting sarcolemmal Na+ entry attenuated reductions in left ventricular compliance during VF and prompted higher mean aortic pressure (110 +/- 7 vs. 95 +/- 11 mmHg, P < 0.001) and higher cardiac work index (159 +/- 34 vs. 126 +/- 29 g x m x min(-1) x kg(-1), P < 0.05) with lesser increases in circulating cardiac troponin I at 60 min PR. CONCLUSIONS Na+ -limiting interventions prevented excess Ca2+ m accumulation induced by ischemia and reperfusion and ameliorated myocardial injury and dysfunction.
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Affiliation(s)
- Sufen Wang
- Department of Medicine, Division of Critical Care Medicine, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois, USA
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41
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Stewart RD, Duhamel TA, Foley KP, Ouyang J, Smith IC, Green HJ. Protection of muscle membrane excitability during prolonged cycle exercise with glucose supplementation. J Appl Physiol (1985) 2007; 103:331-9. [PMID: 17412790 DOI: 10.1152/japplphysiol.01170.2006] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To determine if exercise-induced depressions in neuromuscular function are altered with oral glucose supplementation, 15 untrained participants (Vo2 peak = 45 +/- 2 ml x kg(-1) x min(-1), mean +/- SE) performed prolonged cycle exercise at approximately 60% Vo2 peak on two occasions: without glucose supplementation (NG) and with oral glucose supplementation (G). The oral G began at 30 min of exercise and was administered every 15 min (total ingested = 1.23 +/- 0.11 g carbohydrate/kg body mass). Quadriceps isometric properties and membrane excitability were assessed prior to exercise, after 90 min of exercise, and at fatigue. Cycle time to fatigue was greater (P < 0.05) in G compared with NG (137 +/- 7 vs. 115 +/- 6 min). Progressive reductions (P < 0.05) in maximal voluntary contraction (MVC, N) were observed for NG at 90 min (441 +/- 29) and at fatigue (344 +/- 33) compared with pre-exercise (666 +/- 30). At fatigue in G, the reduction in MVC was not as pronounced (P < 0.05) as in NG. Motor unit activation assessed with the interpolated twitch technique during an MVC following exercise was not different between conditions. During cycling, the G condition also resulted in a higher (P < 0.05) muscle compound potential (M-wave) amplitude (mV) at both 90 min (+50%) and at fatigue (+87%) compared with NG. Similar effects were also found M-wave area (mV/ms). These results suggest that the ergogenic effect of glucose supplementation occurs not as a result of decreased neural activation but to improved muscle function, possibly as a consequence of protection of muscle membrane excitability.
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Affiliation(s)
- R D Stewart
- Department of Kinesiology, University of Waterloo, Waterloo, ON Canada N2L 3G1
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42
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Abstract
To determine whether sarcolemmal and/or mitochondrial ATP-sensitive potassium (K(ATP)) channels (sarcK(ATP), mitoK(ATP)) are involved in stretch-induced protection, isolated isovolumic rat hearts were assigned to the following protocols: nonstretched hearts were subjected to 20 min of global ischemia (Is) and 30 min of reperfusion, and before Is stretched hearts received 5 min of stretch + 10 min of no intervention. Stretch was induced by a transient increase in left ventricular end-diastolic pressure (LVEDP) from 10 to 40 mmHg. Other hearts received 5-hydroxydecanoate (5-HD; 100 microM), a selective inhibitor of mitoK(ATP), or HMR-1098 (20 microM), a selective inhibitor of sarcK(ATP), before the stretch protocol. Systolic function was assessed through left ventricular developed pressure (LVDP) and maximal rise in velocity of left ventricular pressure (+dP/dt(max)) and diastolic function through maximal decrease in velocity of left ventricular pressure (-dP/dt(max)) and LVEDP. Lactate dehydrogenase (LDH) release and ATP content were also measured. Stretch resulted in a significant increase of postischemic recovery and attenuation of diastolic stiffness. At 30 min of reperfusion LVDP and +dP/dt(max) were 87 +/- 4% and 92 +/- 6% and -dP/dt(max) and LVEDP were 95 +/- 9% and 10 +/- 4 mmHg vs. 57 +/- 6%, 53 +/- 6%, 57 +/- 10%, and 28 +/- 5 mmHg, respectively, in nonstretched hearts. Stretch increased ATP content and did not produce LDH release. 5-HD did not modify and HMR-1098 prevented the protection achieved by stretch. Our results show that the beneficial effects of stretch on postischemic myocardial dysfunction, cellular damage, and energetic state involve the participation of sarcK(ATP) but not mitoK(ATP).
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Affiliation(s)
- Susana M Mosca
- Centro de Investigaciones Cardiovasculares, Universidad Nacional de La Plata, 60 y 120, 1900 La Plata, Argentina.
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43
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Danylovych HV, Danylovych IV. [Effect of nitric oxides and hydrogen peroxide on Ca2+, Mg(2+)-ATPase and Mg(2+)-ATPase activity in myometrium sarcolemma]. Ukr Biokhim Zh (1999) 2007; 79:30-37. [PMID: 18030747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The action of sodium nitroprusside, nitrite-anions and hydrogen peroxide on Ca2+, Mg(2+)-ATPase and Mg(2+)-ATPase (Ca(2+)-independent) enzymatic activity in myometrium sarcolemma fraction is investigated. It is established, that 0.1 mM sodium nitroprusside and 10(-8)-10(-5) M nitrite-anions essentially reduce Ca2+, Mg(2+)-ATPase activity whereas Mg(2+)-ATPase proved to be absolutely resistant to them. At rather high concentration of nitrite-anions (0.1 mM) appreciable stimulation of Ca2+, Mg(2+)-ATPase was observed. Hydrogen peroxide (10(-8)-10(-4)), depending on the concentration suppressed both enzymes activity. However, Ca2+, Mg(2+)-ATPase proved to be more sensitive to the action of H2O2 (seeming K(i) = 0.42 +/- 0.1 microM), than Mg(2+)-ATPase (seeming K(i) = 3.1 +/- 0.9 microM). At presence of 1 mM ditiothreitole (a reducer of SH groups of the membrane surface) action of investigated substances considerably decreased. Reagents on carboxic- (dicyclogexilcarbodiimid) and amino- groups of the membrane (trinitrobenzolsulfonic acid) inhibited both Ca2+, Mg(2+)-ATPase, and Mg(2+)-ATPase activity in membrane fractions. In the presence of noted reagents sodium nitroprusside and nitrite-anions action was not almost shown. Hence, nitrogen oxide, nitrite-anions and hydrogen peroxide suppress Ca2+, Mg(2+)-ATPase and Mg(2+)-ATPase (only hydrogen peroxide) activity in the plasmatic membrane of myometrium cells, and this action can be connected with direct updating of superficial chemical groups of the membrane.
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SUKHODUB ANDREY, JOVANOVIĆ SOFIJA, DU QINGYOU, BUDAS GRANT, CLELLAND ALLYSONK, SHEN MEI, SAKAMOTO KEI, TIAN RONG, JOVANOVIĆ ALEKSANDAR. AMP-activated protein kinase mediates preconditioning in cardiomyocytes by regulating activity and trafficking of sarcolemmal ATP-sensitive K(+) channels. J Cell Physiol 2007; 210:224-36. [PMID: 17044064 PMCID: PMC2128052 DOI: 10.1002/jcp.20862] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Brief periods of ischemia and reperfusion that precede sustained ischemia lead to a reduction in myocardial infarct size. This phenomenon, known as ischemic preconditioning, is mediated by signaling pathway(s) that is complex and yet to be fully defined. AMP-activated kinase (AMPK) is activated in cells under conditions associated with ATP depletion and increased AMP/ATP ratio. In the present study, we have taken advantage of a cardiac phenotype overexpressing a dominant negative form of the alpha2 subunit of AMPK to analyze the role, if any, that AMPK plays in preconditioning the heart. We have found that myocardial preconditioning activates AMPK in wild type, but not transgenic mice. Cardiac cells from transgenic mice could not be preconditioned, as opposed to cells from the wild type. The cytoprotective effect of AMPK was not related to the effect that preconditioning has on mitochondrial membrane potential as revealed by JC-1, a mitochondrial membrane potential-sensitive dye, and laser confocal microscopy. In contrast, experiments with di-8-ANEPPS, a sarcolemmal-potential sensitive dye, has demonstrated that intact AMPK activity is required for preconditioning-induced shortening of the action membrane potential. The preconditioning-induced activation of sarcolemmal K(ATP) channels was observed in wild type, but not in transgenic mice. HMR 1098, a selective inhibitor of sarcolemmal K(ATP) channels opening, inhibited preconditioning-induced shortening of action membrane potential as well as cardioprotection afforded by AMPK. Immunoprecipitation followed by Western blotting has shown that AMPK is essential for preconditioning-induced recruitment of sarcolemmal K(ATP) channels. Based on the obtained results, we conclude that AMPK mediates preconditioning in cardiac cells by regulating the activity and recruitment of sarcolemmal K(ATP) channels without being a part of signaling pathway that regulates mitochondrial membrane potential.
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Affiliation(s)
- ANDREY SUKHODUB
- Maternal and Child Health Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - SOFIJA JOVANOVIĆ
- Maternal and Child Health Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - QINGYOU DU
- Maternal and Child Health Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - GRANT BUDAS
- Maternal and Child Health Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - ALLYSON K. CLELLAND
- Maternal and Child Health Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
| | - MEI SHEN
- Department of Medicine, Cardiovascular Division, Nuclear Magnetic Resonance Laboratory for Physiological Chemistry, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - KEI SAKAMOTO
- MRC Protein Phosphorylation Unit, School of Life Sciences, University of Dundee, Dow Street, Dundee, UK
| | - RONG TIAN
- Department of Medicine, Cardiovascular Division, Nuclear Magnetic Resonance Laboratory for Physiological Chemistry, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts
| | - ALEKSANDAR JOVANOVIĆ
- Maternal and Child Health Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee, UK
- Correspondence to: Aleksandar Jovanović, Maternal and Child Health Sciences, Ninewells Hospital and Medical School, University of Dundee, Dundee, DD1 9SY, Scotland, UK. E-mail:
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Thawornkaiwong A, Pantharanontaga J, Wattanapermpool J. Hypersensitivity of myofilament response to Ca2+ in association with maladaptation of estrogen-deficient heart under diabetes complication. Am J Physiol Regul Integr Comp Physiol 2007; 292:R844-51. [PMID: 17038444 DOI: 10.1152/ajpregu.00365.2006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The amelioration of cardioprotective effect of estrogen in diabetes suggests potential interactive action of estrogen and insulin on myofilament activation. We compared Ca2+-dependent Mg2+-ATPase activity of isolated myofibrillar preparations from hearts of sham and 10-wk ovariectomized rats with or without simultaneous 8 wk-induction of diabetes and from diabetic-ovariectomized rats with estrogen and/or insulin supplementation. Similar magnitude of suppressed maximum myofibrillar ATPase activity was demonstrated in ovariectomized, diabetic, and diabetic-ovariectomized rat hearts. Such suppressed activity and the relative suppression in α-myosin heavy chain level in ovariectomy combined with diabetes could be completely restored by estrogen and insulin supplementation. Conversely, the myofilament Ca2+ hypersensitivity detected only in the ovariectomized but not diabetic group was also observed in diabetic-ovariectomized rats, which was restored upon estrogen supplementation. Binding kinetics of β1-adrenergic receptors and immunoblots of β1-adrenoceptors as well as heat shock 72 (HSP72) were analyzed to determine the association of changes in receptors and HSP72 to that of the myofilament response to Ca2+. The amount of β1-adrenoceptors significantly increased concomitant with Ca2+ hypersensitivity of the myofilament, without differences in the receptor binding affinity among the groups. In contrast, changes in HSP72 paralleled that of maximum myofibrillar ATPase activity. These results indicate that hypersensitivity of cardiac myofilament to Ca2+ is specifically induced in ovariectomized rats even under diabetes complication and that alterations in the expression of β1-adrenoceptors may, in part, play a mechanistic role underlying the cardioprotective effects of estrogen that act together with Ca2+ hypersensitivity of the myofilament in determining the gender difference in cardiac activation.
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Affiliation(s)
- Ariyaporn Thawornkaiwong
- Department of Physiology, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand
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46
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Pasdois P, Beauvoit B, Costa ADT, Vinassa B, Tariosse L, Bonoron-Adèle S, Garlid KD, Dos Santos P. Sarcoplasmic ATP-sensitive potassium channel blocker HMR1098 protects the ischemic heart: implication of calcium, complex I, reactive oxygen species and mitochondrial ATP-sensitive potassium channel. J Mol Cell Cardiol 2006; 42:631-42. [PMID: 17306295 DOI: 10.1016/j.yjmcc.2006.12.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2006] [Revised: 11/27/2006] [Accepted: 12/19/2006] [Indexed: 11/30/2022]
Abstract
The aim of this study was to investigate the effects of HMR1098, a selective blocker of sarcolemmal ATP-sensitive potassium channel (sarcK(ATP)), in Langendorff-perfused rat hearts submitted to ischemia and reperfusion. The recovery of heart hemodynamic and mitochondrial function, studied on skinned fibers, was analyzed after 30-min global ischemia followed by 20-min reperfusion. Infarct size was quantified on a regional ischemia model after 2-h reperfusion. We report that the perfusion of 10 microM HMR1098 before ischemia, delays the onset of ischemic contracture, improves recovery of cardiac function upon reperfusion, preserves the mitochondrial architecture, and finally decreases infarct size. This HMR1098-induced cardioprotection is prevented by 1 mM 2-mercaptopropionylglycine, an antioxidant, and by 100 nM nifedipine, an L-type calcium channel blocker. Concomitantly, it is shown that HMR1098 perfusion induces (i) a transient and specific inhibition of the respiratory chain complex I and, (ii) an increase in the averaged intracellular calcium concentration probed by the in situ measurement of indo-1 fluorescence. Finally, all the beneficial effects of HMR1098 were strongly inhibited by 5-hydroxydecanoate and abolished by glibenclamide, two mitoK(ATP) blockers. This study demonstrates that the HMR1098-induced cardioprotection occurs indirectly through extracellular calcium influx, respiratory chain complex inhibition, reactive oxygen species production and mitoK(ATP) opening. Taken together, these data suggest that a functional interaction between sarcK(ATP) and mitoK(ATP) exists in isolated rat heart ischemia model, which is mediated by extracellular calcium influx.
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47
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Abstract
Although the Na+/H+exchanger (NHE) is considered to be involved in regulation of intracellular Ca2+concentration ([Ca2+]i) through the Na+/Ca2+exchanger, the exact mechanisms of its participation in Ca2+handling by cardiomyocytes are not fully understood. Isolated rat cardiomyocytes were treated with or without agents that are known to modify Ca2+movements in cardiomyocytes and exposed to an NHE inhibitor, 5-( N-methyl- N-isobutyl)amiloride (MIA). [Ca2+]iin cardiomyocytes was measured spectrofluorometrically with fura 2-AM in the absence or presence of KCl, a depolarizing agent. MIA increased basal [Ca2+]iand augmented the KCl-induced increase in [Ca2+]iin a concentration-dependent manner. The MIA-induced increase in basal [Ca2+]iwas unaffected by extracellular Ca2+, antagonists of the sarcolemmal (SL) L-type Ca2+channel, and inhibitors of the SL Na+/Ca2+exchanger, SL Ca2+pump ATPase and mitochondrial Ca2+uptake. However, the MIA-induced increase in basal [Ca2+]iwas attenuated by inhibitors of SL Na+-K+-ATPase and sarcoplasmic reticulum (SR) Ca2+transport. On the other hand, the MIA-mediated augmentation of the KCl response was dependent on extracellular Ca2+concentration and attenuated by agents that inhibit SL L-type Ca2+channels, the SL Na+/Ca2+exchanger, SL Na+-K+-ATPase, and SR Ca2+release channels and the SR Ca2+pump. However, the effect of MIA on the KCl-induced increase in [Ca2+]iremained unaffected by treatment with inhibitors of SL Ca2+pump ATPase and mitochondrial Ca2+uptake. MIA and a decrease in extracellular pH lowered intracellular pH and increased basal [Ca2+]i, whereas a decrease in extracellular pH, in contrast to MIA, depressed the KCl-induced increase in [Ca2+]iin cardiomyocytes. These results suggest that NHE may be involved in regulation of [Ca2+]iand that MIA-induced increases in basal [Ca2+]i, as well as augmentation of the KCl-induced increase in [Ca2+]i, in cardiomyocytes are regulated differentially.
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Affiliation(s)
- Harjot K Saini
- Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, University of Manitoba, Winnipeg, MB, Canada R2H 2A6
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Quinlan JG, Wong BL, Niemeier RT, McCullough AS, Levin L, Emanuele M. Poloxamer 188 failed to prevent exercise-induced membrane breakdown in mdx skeletal muscle fibers. Neuromuscul Disord 2006; 16:855-64. [PMID: 17118658 DOI: 10.1016/j.nmd.2006.09.016] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2006] [Revised: 09/23/2006] [Accepted: 09/27/2006] [Indexed: 11/22/2022]
Abstract
We sought to determine the effectiveness of poloxamer 188 (P188) in protecting dystrophin-deficient, mdx skeletal muscle fiber membrane against exercise-induced breaches. mdx mice were treated with either P188 or placebo via intraperitoneal injections and run on a treadmill for 60-90 min. Membrane breakdown was quantified in cross-sections of rectus femoris muscle pretreated with Evans blue dye (in vivo). The mean % dye-penetrated muscle in the P188 and placebo groups was not significantly different in each of three trials. These results contrast with a recent report of P188 being highly effective in protecting the stretch- and dobutamine-stressed mdx heart muscle. The most likely explanations for the disparity are: (1) the exercise stress we used was beyond the protective range of P188, (2) P188 delivery and serum concentration were sub-optimal, or (3) the mdx skeletal myopathy and cardiomyopathy have fundamentally different responses to treatment.
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MESH Headings
- Animals
- Cardiomyopathies/drug therapy
- Cardiomyopathies/metabolism
- Cardiomyopathies/physiopathology
- Cell Membrane Permeability/drug effects
- Cell Membrane Permeability/physiology
- Coloring Agents
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Drug Administration Routes
- Exercise Tolerance/drug effects
- Exercise Tolerance/physiology
- Female
- Injections, Intraperitoneal
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Inbred mdx
- Muscle Contraction/drug effects
- Muscle Contraction/physiology
- Muscle Fibers, Skeletal/drug effects
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Skeletal/pathology
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/physiopathology
- Muscular Dystrophy, Duchenne/drug therapy
- Muscular Dystrophy, Duchenne/metabolism
- Muscular Dystrophy, Duchenne/physiopathology
- Physical Conditioning, Animal/physiology
- Poloxamer/pharmacology
- Poloxamer/therapeutic use
- Sarcolemma/drug effects
- Sarcolemma/metabolism
- Surface-Active Agents/pharmacology
- Surface-Active Agents/therapeutic use
- Treatment Failure
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Affiliation(s)
- John G Quinlan
- Department of Neurology, The University of Cincinnati, 4010 Medical Science Building, Cincinnati, OH 45267-0525, USA.
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49
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Hansen PS, Clarke RJ, Buhagiar KA, Hamilton E, Garcia A, White C, Rasmussen HH. Alloxan-induced diabetes reduces sarcolemmal Na+-K+ pump function in rabbit ventricular myocytes. Am J Physiol Cell Physiol 2006; 292:C1070-7. [PMID: 17020934 DOI: 10.1152/ajpcell.00288.2006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effect of diabetes on sarcolemmal Na(+)-K(+) pump function is important for our understanding of heart disease associated with diabetes and design of its treatment. We induced diabetes characterized by hyperglycemia but no other major metabolic disturbances in rabbits. Ventricular myocytes isolated from diabetic rabbits and controls were voltage clamped and internally perfused with the whole cell patch-clamp technique. Electrogenic Na(+)-K(+) pump current (I(p), arising from the 3:2 Na(+)-to-K(+) exchange ratio) was identified as the shift in holding current induced by Na(+)-K(+) pump blockade with 100 micromol/l ouabain in most experiments. There was no effect of diabetes on I(p) recorded when myocytes were perfused with pipette solutions containing 80 mmol/l Na(+) to nearly saturate intracellular Na(+)-K(+) pump sites. However, diabetes was associated with a significant decrease in I(p) measured when pipette solutions contained 10 mmol/l Na(+). The decrease was independent of membrane voltage but dependent on the intracellular concentration of K(+). There was no effect of diabetes on the sensitivity of I(p) to extracellular K(+). Pump inhibition was abolished by restoration of euglycemia or by in vivo angiotensin II receptor blockade with losartan. We conclude that diabetes induces sarcolemmal Na(+)-K(+) pump inhibition that can be reversed with pharmacological intervention.
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Affiliation(s)
- Peter S Hansen
- Dept. of Cardiology, Royal North Shore Hospital, St. Leonards, NSW 2065, Australia
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50
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Abstract
Cardiac hypertrophy occurs in as many as 47% of normotensive individuals who chronically use cocaine. We investigated the effects of cocaine, in concentrations commonly found in chronic cocaine users, on calcium/calmodulin kinase (CaMK), and whether cocaine can activate CaMK, increase cardiac myocyte protein expression, and cause cardiac hypertrophy in this manner. In series I to III, 0 (control) or cocaine in concentrations of 10 to 10 mol/L was added to cultured adult rat cardiac ventricular myocytes to determine by Western blots and by P incorporation the optimal treatment time and the optimal dose for CaMK activation. In series I, cocaine, 10 mol/L, increased myocyte CaMKII translocation from myocyte soluble to particulate fractions by > or =73 +/- 9% (P < 0.01) in comparison with controls but did not cause the translocation of CaMKI or CaMKIV. In series II and III, cocaine treatment of myocytes for 15 minutes increased maximal CaMKII activity by 86.5 +/- 13.3% (P < 0.001) and a cocaine dose of 5 x 10 mol/L increased CaMKII activity by 169.5 +/- 18.1% (P < 0.001). In series IV we measured by silver staining beta-myosin heavy chain protein (beta-MHC) expression in myocytes before and after cocaine and also CaMK inhibition with KN-62 (1-[N,O-bis-(5-isoquinolinesulfonyl)-N-methyl-L-tyrosyl]-4-phenylpiperazine). In these experiments, cocaine, 5x10 mol/L, increased myocyte protein concentration by 29.2 +/- 2.8%, and beta-MHC by 93.2 +/- 8.8% (P < 0.001). In series V and VI, cocaine effects on calcium currents (ICa) and intracellular Ca ([Ca]i) were determined before and after CaMK inhibition with KN-62 in rat myocytes. Cocaine, 10 mol/L, enhanced ICa peak amplitude in a voltage-dependent manner (by 173.9 +/- 14.9% at -20 mV and by 38.4 +/- 6.9% at 0 mV P < 0.01). Cocaine, 10 to 10 mol/L, in series VI promoted Ca transients from myocyte sarcoplasmic reticulum and increased [Ca]i to 607 +/- 141 x 10 mol/L (P < 0.05). KN-62 decreased cocaine-induced myocyte protein expression by 76.6%, and beta-MHC by 66.2% (P < 0.01) and significantly decreased cocaine-induced Ca transients and [Ca]i. We conclude that CaMKII activation is an important mechanism whereby cocaine can cause myocyte hypertrophy.
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Affiliation(s)
- Robert J Henning
- Department of Medicine, University of South Florida College of Medicine and the James A. Haley VA Hospital, Tampa, Florida 33612, USA.
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